21059331 has 4 divisors (see below), whose sum is σ = 28079112. Its totient is φ = 14039552.

The previous prime is 21059309. The next prime is 21059347. The reversal of 21059331 is 13395012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21059331 - 2⁹ = 21058819 is a prime.

It is a super-2 number, since 2×21059331² = 886990844335122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21059371) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3509886 + ... + 3509891.

It is an arithmetic number, because the mean of its divisors is an integer number (7019778).

Almost surely, 2^21059331 is an apocalyptic number.

21059331 is a deficient number, since it is larger than the sum of its proper divisors (7019781).

21059331 is an equidigital number, since it uses as much as digits as its factorization.

21059331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7019780.

The product of its (nonzero) digits is 810, while the sum is 24.

The square root of 21059331 is about 4589.0446718244. The cubic root of 21059331 is about 276.1519982969.

The spelling of 21059331 in words is "twenty-one million, fifty-nine thousand, three hundred thirty-one".