21691022 has 4 divisors (see below), whose sum is σ = 32536536. Its totient is φ = 10845510.

The previous prime is 21691013. The next prime is 21691037. The reversal of 21691022 is 22019612.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5422754 + ... + 5422757.

It is an arithmetic number, because the mean of its divisors is an integer number (8134134).

Almost surely, 2^21691022 is an apocalyptic number.

21691022 is a deficient number, since it is larger than the sum of its proper divisors (10845514).

21691022 is a wasteful number, since it uses less digits than its factorization.

21691022 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10845513.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21691022 is about 4657.3621289309. The cubic root of 21691022 is about 278.8859731963.

The spelling of 21691022 in words is "twenty-one million, six hundred ninety-one thousand, twenty-two".