21233690 has 8 divisors (see below), whose sum is σ = 38220660. Its totient is φ = 8493472.

The previous prime is 21233689. The next prime is 21233753. The reversal of 21233690 is 9633212.

It can be written as a sum of positive squares in 2 ways, for example, as 20457529 + 776161 = 4523^2 + 881^2 .

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

It is a super-2 number, since 2×21233690² = 901739182032200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1061675 + ... + 1061694.

Almost surely, 2^21233690 is an apocalyptic number.

21233690 is a deficient number, since it is larger than the sum of its proper divisors (16986970).

21233690 is a wasteful number, since it uses less digits than its factorization.

21233690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2123376.

The product of its (nonzero) digits is 1944, while the sum is 26.

The square root of 21233690 is about 4608.0028211797. The cubic root of 21233690 is about 276.9120305225.

Subtracting from 21233690 its sum of digits (26), we obtain a square (21233664 = 4608²).

The spelling of 21233690 in words is "twenty-one million, two hundred thirty-three thousand, six hundred ninety".