78990031 has 4 divisors (see below), whose sum is σ = 79122064. Its totient is φ = 78858000.

The previous prime is 78990013. The next prime is 78990047. The reversal of 78990031 is 13009987.

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

It is a cyclic number.

It is not a de Polignac number, because 78990031 - 2¹¹ = 78987983 is a prime.

It is a super-2 number, since 2×78990031² = 12478849994761922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78990061) 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, 65115 + ... + 66316.

It is an arithmetic number, because the mean of its divisors is an integer number (19780516).

Almost surely, 2^78990031 is an apocalyptic number.

78990031 is a deficient number, since it is larger than the sum of its proper divisors (132033).

78990031 is a wasteful number, since it uses less digits than its factorization.

78990031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132032.

The product of its (nonzero) digits is 13608, while the sum is 37.

The square root of 78990031 is about 8887.6335995584. The cubic root of 78990031 is about 429.0659932564.

The spelling of 78990031 in words is "seventy-eight million, nine hundred ninety thousand, thirty-one".