21820474 has 16 divisors (see below), whose sum is σ = 37104480. Its totient is φ = 9540720.

The previous prime is 21820459. The next prime is 21820481. The reversal of 21820474 is 47402812.

It is a super-2 number, since 2×21820474² = 952266171169352, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21592 + ... + 22579.

It is an arithmetic number, because the mean of its divisors is an integer number (2319030).

Almost surely, 2^21820474 is an apocalyptic number.

21820474 is a deficient number, since it is larger than the sum of its proper divisors (15284006).

21820474 is a wasteful number, since it uses less digits than its factorization.

21820474 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44205.

The product of its (nonzero) digits is 3584, while the sum is 28.

The square root of 21820474 is about 4671.2390219298. The cubic root of 21820474 is about 279.4396702449.

The spelling of 21820474 in words is "twenty-one million, eight hundred twenty thousand, four hundred seventy-four".