65438991 has 12 divisors (see below), whose sum is σ = 96721768. Its totient is φ = 42611184.

The previous prime is 65438987. The next prime is 65439029. The reversal of 65438991 is 19983456.

It is a happy number.

It is not a de Polignac number, because 65438991 - 2² = 65438987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65438951) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 84160 + ... + 84933.

Almost surely, 2^65438991 is an apocalyptic number.

65438991 is a deficient number, since it is larger than the sum of its proper divisors (31282777).

65438991 is a wasteful number, since it uses less digits than its factorization.

65438991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169142 (or 169139 counting only the distinct ones).

The product of its digits is 233280, while the sum is 45.

The square root of 65438991 is about 8089.4370014235. The cubic root of 65438991 is about 402.9757059573.

The spelling of 65438991 in words is "sixty-five million, four hundred thirty-eight thousand, nine hundred ninety-one".