820013257 has 8 divisors (see below), whose sum is σ = 937486656. Its totient is φ = 702622032.

The previous prime is 820013177. The next prime is 820013263. The reversal of 820013257 is 752310028.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-820013257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820053257) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2583 + ... + 40579.

It is an arithmetic number, because the mean of its divisors is an integer number (117185832).

Almost surely, 2^820013257 is an apocalyptic number.

It is an amenable number.

820013257 is a deficient number, since it is larger than the sum of its proper divisors (117473399).

820013257 is a wasteful number, since it uses less digits than its factorization.

820013257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41087.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 820013257 is about 28635.8736028779. The cubic root of 820013257 is about 935.9952063607.

It can be divided in two parts, 82001 and 3257, that added together give a palindrome (85258).

The spelling of 820013257 in words is "eight hundred twenty million, thirteen thousand, two hundred fifty-seven".