78777431402 has 4 divisors (see below), whose sum is σ = 118166147106. Its totient is φ = 39388715700.

The previous prime is 78777431389. The next prime is 78777431407. The reversal of 78777431402 is 20413477787.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 68324209321 + 10453222081 = 261389^2 + 102241^2 .

It is not an unprimeable number, because it can be changed into a prime (78777431407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19694357849 + ... + 19694357852.

Almost surely, 2^78777431402 is an apocalyptic number.

78777431402 is a deficient number, since it is larger than the sum of its proper divisors (39388715704).

78777431402 is a wasteful number, since it uses less digits than its factorization.

78777431402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39388715703.

The product of its (nonzero) digits is 1843968, while the sum is 50.

The spelling of 78777431402 in words is "seventy-eight billion, seven hundred seventy-seven million, four hundred thirty-one thousand, four hundred two".