977777661 has 32 divisors (see below), whose sum is σ = 1592967168. Its totient is φ = 520738560.

The previous prime is 977777657. The next prime is 977777681. The reversal of 977777661 is 166777779.

It is not a de Polignac number, because 977777661 - 2² = 977777657 is a prime.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (977777611) 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, 23476 + ... + 50066.

It is an arithmetic number, because the mean of its divisors is an integer number (49780224).

Almost surely, 2^977777661 is an apocalyptic number.

It is an amenable number.

977777661 is a deficient number, since it is larger than the sum of its proper divisors (615189507).

977777661 is a wasteful number, since it uses less digits than its factorization.

977777661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26721.

The product of its digits is 5445468, while the sum is 57.

The square root of 977777661 is about 31269.4365315399. The cubic root of 977777661 is about 992.5369957890.

The spelling of 977777661 in words is "nine hundred seventy-seven million, seven hundred seventy-seven thousand, six hundred sixty-one".