65257491 has 16 divisors (see below), whose sum is σ = 94267040. Its totient is φ = 40154400.

The previous prime is 65257487. The next prime is 65257541. The reversal of 65257491 is 19475256.

It is not a de Polignac number, because 65257491 - 2² = 65257487 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65257091) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1641 + ... + 11541.

It is an arithmetic number, because the mean of its divisors is an integer number (5891690).

Almost surely, 2^65257491 is an apocalyptic number.

65257491 is a deficient number, since it is larger than the sum of its proper divisors (29009549).

65257491 is an equidigital number, since it uses as much as digits as its factorization.

65257491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9943 (or 9917 counting only the distinct ones).

The product of its digits is 75600, while the sum is 39.

The square root of 65257491 is about 8078.2108786538. The cubic root of 65257491 is about 402.6027997650.

The spelling of 65257491 in words is "sixty-five million, two hundred fifty-seven thousand, four hundred ninety-one".