65139640 has 16 divisors (see below), whose sum is σ = 146564280. Its totient is φ = 26055840.

The previous prime is 65139629. The next prime is 65139653. The reversal of 65139640 is 4693156.

It is a junction number, because it is equal to n+sod(n) for n = 65139596 and 65139605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 814206 + ... + 814285.

Almost surely, 2^65139640 is an apocalyptic number.

It is an amenable number.

65139640 is an abundant number, since it is smaller than the sum of its proper divisors (81424640).

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

65139640 is a wasteful number, since it uses less digits than its factorization.

65139640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1628502 (or 1628498 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 34.

The square root of 65139640 is about 8070.9132073143. The cubic root of 65139640 is about 402.3602951232.

The spelling of 65139640 in words is "sixty-five million, one hundred thirty-nine thousand, six hundred forty".