77905512 has 48 divisors (see below), whose sum is σ = 211444740. Its totient is φ = 25913088.

The previous prime is 77905507. The next prime is 77905517. The reversal of 77905512 is 21550977.

It is an interprime number because it is at equal distance from previous prime (77905507) and next prime (77905517).

It can be written as a sum of positive squares in 2 ways, for example, as 73719396 + 4186116 = 8586^2 + 2046^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (77905517) 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 11 ways as a sum of consecutive naturals, for example, 46188 + ... + 47844.

Almost surely, 2^77905512 is an apocalyptic number.

77905512 is a gapful number since it is divisible by the number (72) formed by its first and last digit.

It is an amenable number.

77905512 is an abundant number, since it is smaller than the sum of its proper divisors (133539228).

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

77905512 is a wasteful number, since it uses less digits than its factorization.

77905512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2322 (or 2315 counting only the distinct ones).

The product of its (nonzero) digits is 22050, while the sum is 36.

The square root of 77905512 is about 8826.4099157019. The cubic root of 77905512 is about 427.0932706906.

The spelling of 77905512 in words is "seventy-seven million, nine hundred five thousand, five hundred twelve".