678399131 has 4 divisors (see below), whose sum is σ = 679506432. Its totient is φ = 677291832.

The previous prime is 678399121. The next prime is 678399143. The reversal of 678399131 is 131993876.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-678399131 is a prime.

It is a super-2 number, since 2×678399131² = 920450761883110322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (678399121) 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, 552731 + ... + 553956.

It is an arithmetic number, because the mean of its divisors is an integer number (169876608).

Almost surely, 2^678399131 is an apocalyptic number.

678399131 is a deficient number, since it is larger than the sum of its proper divisors (1107301).

678399131 is a wasteful number, since it uses less digits than its factorization.

678399131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1107300.

The product of its digits is 244944, while the sum is 47.

The square root of 678399131 is about 26046.0962718024. The cubic root of 678399131 is about 878.6753188295.

The spelling of 678399131 in words is "six hundred seventy-eight million, three hundred ninety-nine thousand, one hundred thirty-one".