7921257 has 8 divisors (see below), whose sum is σ = 10710720. Its totient is φ = 5206320.

The previous prime is 7921247. The next prime is 7921259. The reversal of 7921257 is 7521297.

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

It is not a de Polignac number, because 7921257 - 2⁷ = 7921129 is a prime.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (7921259) 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, 18382 + ... + 18807.

It is an arithmetic number, because the mean of its divisors is an integer number (1338840).

Almost surely, 2^7921257 is an apocalyptic number.

It is an amenable number.

7921257 is a deficient number, since it is larger than the sum of its proper divisors (2789463).

7921257 is a wasteful number, since it uses less digits than its factorization.

7921257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37263.

The product of its digits is 8820, while the sum is 33.

The square root of 7921257 is about 2814.4727747839. The cubic root of 7921257 is about 199.3416435452.

The spelling of 7921257 in words is "seven million, nine hundred twenty-one thousand, two hundred fifty-seven".