77981251478 has 8 divisors (see below), whose sum is σ = 125969713968. Its totient is φ = 35991346824.

The previous prime is 77981251457. The next prime is 77981251483. The reversal of 77981251478 is 87415218977.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1499639426 + ... + 1499639477.

It is an arithmetic number, because the mean of its divisors is an integer number (15746214246).

Almost surely, 2^77981251478 is an apocalyptic number.

77981251478 is a deficient number, since it is larger than the sum of its proper divisors (47988462490).

77981251478 is a wasteful number, since it uses less digits than its factorization.

77981251478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2999278918.

The product of its digits is 7902720, while the sum is 59.

The spelling of 77981251478 in words is "seventy-seven billion, nine hundred eighty-one million, two hundred fifty-one thousand, four hundred seventy-eight".