21183990 has 16 divisors (see below), whose sum is σ = 50841648. Its totient is φ = 5649056.

The previous prime is 21183977. The next prime is 21184027. The reversal of 21183990 is 9938112.

It is a super-2 number, since 2×21183990² = 897522864640200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 353037 + ... + 353096.

It is an arithmetic number, because the mean of its divisors is an integer number (3177603).

Almost surely, 2^21183990 is an apocalyptic number.

21183990 is an abundant number, since it is smaller than the sum of its proper divisors (29657658).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21183990 is a wasteful number, since it uses less digits than its factorization.

21183990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 706143.

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 21183990 is about 4602.6068700249. The cubic root of 21183990 is about 276.6958131259.

The spelling of 21183990 in words is "twenty-one million, one hundred eighty-three thousand, nine hundred ninety".