21901630 has 32 divisors (see below), whose sum is σ = 40543776. Its totient is φ = 8515584.

The previous prime is 21901619. The next prime is 21901631. The reversal of 21901630 is 3610912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21901631) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 64822 + ... + 65158.

It is an arithmetic number, because the mean of its divisors is an integer number (1266993).

Almost surely, 2^21901630 is an apocalyptic number.

21901630 is a deficient number, since it is larger than the sum of its proper divisors (18642146).

21901630 is a wasteful number, since it uses less digits than its factorization.

21901630 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 508.

The product of its (nonzero) digits is 324, while the sum is 22.

The square root of 21901630 is about 4679.9177343197. The cubic root of 21901630 is about 279.7856778286.

The spelling of 21901630 in words is "twenty-one million, nine hundred one thousand, six hundred thirty".