121220100 has 81 divisors (see below), whose sum is σ = 380995797. Its totient is φ = 32237280.

The previous prime is 121220069. The next prime is 121220101. The reversal of 121220100 is 1022121.

The square root of 121220100 is 11010.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 43639236 + 77580864 = 6606^2 + 8808^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (121220101) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 330117 + ... + 330483.

Almost surely, 2^121220100 is an apocalyptic number.

121220100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

121220100 is the 11010-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121220100

121220100 is an abundant number, since it is smaller than the sum of its proper divisors (259775697).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121220100 is a wasteful number, since it uses less digits than its factorization.

121220100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 754 (or 377 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The cubic root of 121220100 is about 494.9084617999.

Adding to 121220100 its reverse (1022121), we get a palindrome (122242221).

Multiplying 121220100 by its reverse (1022121), we get a square (123901609832100 = 11131110²).

It can be divided in two parts, 1212 and 20100, that added together give a palindrome (21312).

The spelling of 121220100 in words is "one hundred twenty-one million, two hundred twenty thousand, one hundred".