21351982 has 8 divisors (see below), whose sum is σ = 32571000. Its totient is φ = 10494984.

The previous prime is 21351977. The next prime is 21352007. The reversal of 21351982 is 28915312.

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

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 90357 + ... + 90592.

It is an arithmetic number, because the mean of its divisors is an integer number (4071375).

Almost surely, 2^21351982 is an apocalyptic number.

21351982 is a deficient number, since it is larger than the sum of its proper divisors (11219018).

21351982 is a wasteful number, since it uses less digits than its factorization.

21351982 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181010.

The product of its digits is 4320, while the sum is 31.

The square root of 21351982 is about 4620.8204899130. The cubic root of 21351982 is about 277.4253003492.

The spelling of 21351982 in words is "twenty-one million, three hundred fifty-one thousand, nine hundred eighty-two".