77771961 has 8 divisors (see below), whose sum is σ = 115217760. Its totient is φ = 51847956.

The previous prime is 77771933. The next prime is 77771983. The reversal of 77771961 is 16917777.

It is not a de Polignac number, because 77771961 - 2⁷ = 77771833 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77771461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1440195 + ... + 1440248.

It is an arithmetic number, because the mean of its divisors is an integer number (14402220).

Almost surely, 2^77771961 is an apocalyptic number.

It is an amenable number.

77771961 is a deficient number, since it is larger than the sum of its proper divisors (37445799).

77771961 is a wasteful number, since it uses less digits than its factorization.

77771961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2880452 (or 2880446 counting only the distinct ones).

The product of its digits is 129654, while the sum is 45.

The square root of 77771961 is about 8818.8412504138. The cubic root of 77771961 is about 426.8490801909.

The spelling of 77771961 in words is "seventy-seven million, seven hundred seventy-one thousand, nine hundred sixty-one".