7928921 has 24 divisors (see below), whose sum is σ = 10766784. Its totient is φ = 5639040.

The previous prime is 7928911. The next prime is 7928923. The reversal of 7928921 is 1298297.

7928921 = 844² + 845² + ... + 854².

It is not a de Polignac number, because 7928921 - 2⁶ = 7928857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (7928923) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 89045 + ... + 89133.

It is an arithmetic number, because the mean of its divisors is an integer number (448616).

Almost surely, 2^7928921 is an apocalyptic number.

It is an amenable number.

7928921 is a deficient number, since it is larger than the sum of its proper divisors (2837863).

7928921 is a wasteful number, since it uses less digits than its factorization.

7928921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209 (or 120 counting only the distinct ones).

The product of its digits is 18144, while the sum is 38.

The square root of 7928921 is about 2815.8339794810. The cubic root of 7928921 is about 199.4059120448.

The spelling of 7928921 in words is "seven million, nine hundred twenty-eight thousand, nine hundred twenty-one".