21022331 has 4 divisors (see below), whose sum is σ = 22933464. Its totient is φ = 19111200.

The previous prime is 21022279. The next prime is 21022357. The reversal of 21022331 is 13322012.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21022331 is a prime.

It is a super-2 number, since 2×21022331² = 883876801347122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21021331) 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, 955550 + ... + 955571.

It is an arithmetic number, because the mean of its divisors is an integer number (5733366).

Almost surely, 2^21022331 is an apocalyptic number.

21022331 is a deficient number, since it is larger than the sum of its proper divisors (1911133).

21022331 is a wasteful number, since it uses less digits than its factorization.

21022331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1911132.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21022331 is about 4585.0115594184. The cubic root of 21022331 is about 275.9901759088.

Adding to 21022331 its reverse (13322012), we get a palindrome (34344343).

The spelling of 21022331 in words is "twenty-one million, twenty-two thousand, three hundred thirty-one".