686515972 has 12 divisors (see below), whose sum is σ = 1230705756. Its totient is φ = 334885760.

The previous prime is 686515967. The next prime is 686515979. The reversal of 686515972 is 279515686.

It can be written as a sum of positive squares in 2 ways, for example, as 213627456 + 472888516 = 14616^2 + 21746^2 .

It is a super-2 number, since 2×686515972² = 942608359622209568, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (686515979) 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, 2092873 + ... + 2093200.

It is an arithmetic number, because the mean of its divisors is an integer number (102558813).

Almost surely, 2^686515972 is an apocalyptic number.

It is an amenable number.

686515972 is a deficient number, since it is larger than the sum of its proper divisors (544189784).

686515972 is a wasteful number, since it uses less digits than its factorization.

686515972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4186118 (or 4186116 counting only the distinct ones).

The product of its digits is 907200, while the sum is 49.

The square root of 686515972 is about 26201.4498072149. The cubic root of 686515972 is about 882.1657965135.

The spelling of 686515972 in words is "six hundred eighty-six million, five hundred fifteen thousand, nine hundred seventy-two".