21910438 has 24 divisors (see below), whose sum is σ = 37116576. Its totient is φ = 9686160.

The previous prime is 21910409. The next prime is 21910453. The reversal of 21910438 is 83401912.

It is a happy number.

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 11 ways as a sum of consecutive naturals, for example, 7731 + ... + 10177.

It is an arithmetic number, because the mean of its divisors is an integer number (1546524).

Almost surely, 2^21910438 is an apocalyptic number.

21910438 is a deficient number, since it is larger than the sum of its proper divisors (15206138).

21910438 is a wasteful number, since it uses less digits than its factorization.

21910438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2508 (or 2497 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 21910438 is about 4680.8586819087. The cubic root of 21910438 is about 279.8231791770.

The spelling of 21910438 in words is "twenty-one million, nine hundred ten thousand, four hundred thirty-eight".