1621401600 has 672 divisors, whose sum is σ = 6825813120. Its totient is φ = 330301440.

The previous prime is 1621401553. The next prime is 1621401611. The reversal of 1621401600 is 61041261.

It is a tau number, because it is divible by the number of its divisors (672).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 55910386 + ... + 55910414.

It is an arithmetic number, because the mean of its divisors is an integer number (10157460).

Almost surely, 2^1621401600 is an apocalyptic number.

1621401600 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1621401600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3412906560).

1621401600 is an abundant number, since it is smaller than the sum of its proper divisors (5204411520).

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

1621401600 is a wasteful number, since it uses less digits than its factorization.

1621401600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88 (or 59 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 1621401600 is about 40266.6313465629. The cubic root of 1621401600 is about 1174.7989032642.

Adding to 1621401600 its reverse (61041261), we get a palindrome (1682442861).

The spelling of 1621401600 in words is "one billion, six hundred twenty-one million, four hundred one thousand, six hundred".