21921410 has 16 divisors (see below), whose sum is σ = 45095616. Its totient is φ = 7515888.

The previous prime is 21921407. The next prime is 21921413. The reversal of 21921410 is 1412912.

It is an interprime number because it is at equal distance from previous prime (21921407) and next prime (21921413).

It is not an unprimeable number, because it can be changed into a prime (21921413) 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 7 ways as a sum of consecutive naturals, for example, 156512 + ... + 156651.

It is an arithmetic number, because the mean of its divisors is an integer number (2818476).

Almost surely, 2^21921410 is an apocalyptic number.

21921410 is an abundant number, since it is smaller than the sum of its proper divisors (23174206).

21921410 is a wasteful number, since it uses less digits than its factorization.

21921410 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 313177.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 21921410 is about 4682.0305424036. The cubic root of 21921410 is about 279.8698800170.

The spelling of 21921410 in words is "twenty-one million, nine hundred twenty-one thousand, four hundred ten".