21151490 has 32 divisors (see below), whose sum is σ = 40715136. Its totient is φ = 7891840.

The previous prime is 21151489. The next prime is 21151561. The reversal of 21151490 is 9415112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8309 + ... + 10551.

It is an arithmetic number, because the mean of its divisors is an integer number (1272348).

Almost surely, 2^21151490 is an apocalyptic number.

21151490 is a deficient number, since it is larger than the sum of its proper divisors (19563646).

21151490 is a wasteful number, since it uses less digits than its factorization.

21151490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2314.

The product of its (nonzero) digits is 360, while the sum is 23.

The square root of 21151490 is about 4599.0749069786. The cubic root of 21151490 is about 276.5542405420.

The spelling of 21151490 in words is "twenty-one million, one hundred fifty-one thousand, four hundred ninety".