21903538 has 8 divisors (see below), whose sum is σ = 32908032. Its totient is φ = 10934196.

The previous prime is 21903533. The next prime is 21903569. The reversal of 21903538 is 83530912.

It is a happy number.

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

It is not an unprimeable number, because it can be changed into a prime (21903533) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7170 + ... + 9757.

It is an arithmetic number, because the mean of its divisors is an integer number (4113504).

Almost surely, 2^21903538 is an apocalyptic number.

21903538 is a deficient number, since it is larger than the sum of its proper divisors (11004494).

21903538 is a wasteful number, since it uses less digits than its factorization.

21903538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17576.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 21903538 is about 4680.1215796174. The cubic root of 21903538 is about 279.7938022707.

The spelling of 21903538 in words is "twenty-one million, nine hundred three thousand, five hundred thirty-eight".