21088331 has 4 divisors (see below), whose sum is σ = 23005464. Its totient is φ = 19171200.

The previous prime is 21088321. The next prime is 21088337. The reversal of 21088331 is 13388012.

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 21088331 - 2²² = 16894027 is a prime.

It is a super-2 number, since 2×21088331² = 889435408731122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21088331.

It is not an unprimeable number, because it can be changed into a prime (21088337) 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, 958550 + ... + 958571.

It is an arithmetic number, because the mean of its divisors is an integer number (5751366).

Almost surely, 2^21088331 is an apocalyptic number.

21088331 is a deficient number, since it is larger than the sum of its proper divisors (1917133).

21088331 is a wasteful number, since it uses less digits than its factorization.

21088331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1917132.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 21088331 is about 4592.2032838279. The cubic root of 21088331 is about 276.2786996111.

The spelling of 21088331 in words is "twenty-one million, eighty-eight thousand, three hundred thirty-one".