77122220 has 96 divisors (see below), whose sum is σ = 197987328. Its totient is φ = 24659712.

The previous prime is 77122219. The next prime is 77122229. The reversal of 77122220 is 2222177.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is not an unprimeable number, because it can be changed into a prime (77122229) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 138182 + ... + 138738.

It is an arithmetic number, because the mean of its divisors is an integer number (2062368).

Almost surely, 2^77122220 is an apocalyptic number.

77122220 is a gapful number since it is divisible by the number (70) 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 77122220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (98993664).

77122220 is an abundant number, since it is smaller than the sum of its proper divisors (120865108).

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

77122220 is a wasteful number, since it uses less digits than its factorization.

77122220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 639 (or 637 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 23.

The square root of 77122220 is about 8781.9257569169. The cubic root of 77122220 is about 425.6570597716.

Adding to 77122220 its reverse (2222177), we get a palindrome (79344397).

The spelling of 77122220 in words is "seventy-seven million, one hundred twenty-two thousand, two hundred twenty".