21901039 has 4 divisors (see below), whose sum is σ = 21910824. Its totient is φ = 21891256.

The previous prime is 21901021. The next prime is 21901051. The reversal of 21901039 is 93010912.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21901039 - 2⁵ = 21901007 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21901079) 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, 309 + ... + 6625.

It is an arithmetic number, because the mean of its divisors is an integer number (5477706).

Almost surely, 2^21901039 is an apocalyptic number.

21901039 is a deficient number, since it is larger than the sum of its proper divisors (9785).

21901039 is an equidigital number, since it uses as much as digits as its factorization.

21901039 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9784.

The product of its (nonzero) digits is 486, while the sum is 25.

The square root of 21901039 is about 4679.8545917582. The cubic root of 21901039 is about 279.7831611997.

The spelling of 21901039 in words is "twenty-one million, nine hundred one thousand, thirty-nine".