78135978 has 16 divisors (see below), whose sum is σ = 165464640. Its totient is φ = 24513216.

The previous prime is 78135943. The next prime is 78135979. The reversal of 78135978 is 87953187.

It is a super-2 number, since 2×78135978² = 12210462116032968, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (78135979) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 382918 + ... + 383121.

It is an arithmetic number, because the mean of its divisors is an integer number (10341540).

Almost surely, 2^78135978 is an apocalyptic number.

78135978 is an abundant number, since it is smaller than the sum of its proper divisors (87328662).

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

78135978 is a wasteful number, since it uses less digits than its factorization.

78135978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 766061.

The product of its digits is 423360, while the sum is 48.

The square root of 78135978 is about 8839.4557524771. The cubic root of 78135978 is about 427.5140093217.

The spelling of 78135978 in words is "seventy-eight million, one hundred thirty-five thousand, nine hundred seventy-eight".