21790642 has 8 divisors (see below), whose sum is σ = 32706432. Its totient is φ = 10888500.

The previous prime is 21790633. The next prime is 21790673. The reversal of 21790642 is 24609712.

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

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, 2967 + ... + 7237.

It is an arithmetic number, because the mean of its divisors is an integer number (4088304).

Almost surely, 2^21790642 is an apocalyptic number.

21790642 is a deficient number, since it is larger than the sum of its proper divisors (10915790).

21790642 is a wasteful number, since it uses less digits than its factorization.

21790642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6824.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 21790642 is about 4668.0447727073. The cubic root of 21790642 is about 279.3122662586.

The spelling of 21790642 in words is "twenty-one million, seven hundred ninety thousand, six hundred forty-two".