77972138 has 8 divisors (see below), whose sum is σ = 117634788. Its totient is φ = 38760544.

The previous prime is 77972137. The next prime is 77972159. The reversal of 77972138 is 83127977.

It can be written as a sum of positive squares in 2 ways, for example, as 71351809 + 6620329 = 8447^2 + 2573^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (77972137) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 112331 + ... + 113022.

Almost surely, 2^77972138 is an apocalyptic number.

77972138 is a deficient number, since it is larger than the sum of its proper divisors (39662650).

77972138 is a wasteful number, since it uses less digits than its factorization.

77972138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225528.

The product of its digits is 148176, while the sum is 44.

The square root of 77972138 is about 8830.1833503048. The cubic root of 77972138 is about 427.2149882580.

The spelling of 77972138 in words is "seventy-seven million, nine hundred seventy-two thousand, one hundred thirty-eight".