77901021 has 80 divisors (see below), whose sum is σ = 139043520. Its totient is φ = 42923520.

The previous prime is 77901017. The next prime is 77901059. The reversal of 77901021 is 12010977.

It is not a de Polignac number, because 77901021 - 2² = 77901017 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77901011) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 560370 + ... + 560508.

It is an arithmetic number, because the mean of its divisors is an integer number (1738044).

Almost surely, 2^77901021 is an apocalyptic number.

It is an amenable number.

77901021 is a deficient number, since it is larger than the sum of its proper divisors (61142499).

77901021 is a wasteful number, since it uses less digits than its factorization.

77901021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216 (or 207 counting only the distinct ones).

The product of its (nonzero) digits is 882, while the sum is 27.

The square root of 77901021 is about 8826.1555050883. The cubic root of 77901021 is about 427.0850636858.

Adding to 77901021 its reverse (12010977), we get a palindrome (89911998).

The spelling of 77901021 in words is "seventy-seven million, nine hundred one thousand, twenty-one".