21901539 has 8 divisors (see below), whose sum is σ = 31856832. Its totient is φ = 13273640.

The previous prime is 21901519. The next prime is 21901571. The reversal of 21901539 is 93510912.

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

It is a cyclic number.

It is not a de Polignac number, because 21901539 - 2¹¹ = 21899491 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21901519) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 331809 + ... + 331874.

It is an arithmetic number, because the mean of its divisors is an integer number (3982104).

Almost surely, 2^21901539 is an apocalyptic number.

21901539 is a deficient number, since it is larger than the sum of its proper divisors (9955293).

21901539 is a wasteful number, since it uses less digits than its factorization.

21901539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 663697.

The product of its (nonzero) digits is 2430, while the sum is 30.

The square root of 21901539 is about 4679.9080119165. The cubic root of 21901539 is about 279.7852903303.

The spelling of 21901539 in words is "twenty-one million, nine hundred one thousand, five hundred thirty-nine".