977665555321 has 16 divisors (see below), whose sum is σ = 1266611248000. Its totient is φ = 732825076608.

The previous prime is 977665555313. The next prime is 977665555337. The reversal of 977665555321 is 123555566779.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 977665555321 - 2³ = 977665555313 is a prime.

It is a super-2 number, since 2×977665555321² (a number of 25 digits) contains 22 as substring.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 977665555321.

It is not an unprimeable number, because it can be changed into a prime (977665555351) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 282723996 + ... + 282727453.

It is an arithmetic number, because the mean of its divisors is an integer number (79163203000).

Almost surely, 2^977665555321 is an apocalyptic number.

977665555321 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

It is an amenable number.

977665555321 is a deficient number, since it is larger than the sum of its proper divisors (288945692679).

977665555321 is a wasteful number, since it uses less digits than its factorization.

977665555321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 565451488.

The product of its digits is 59535000, while the sum is 61.

The spelling of 977665555321 in words is "nine hundred seventy-seven billion, six hundred sixty-five million, five hundred fifty-five thousand, three hundred twenty-one".