21897039 has 16 divisors (see below), whose sum is σ = 29804544. Its totient is φ = 14296800.

The previous prime is 21897017. The next prime is 21897053. The reversal of 21897039 is 93079812.

It is not a de Polignac number, because 21897039 - 2¹¹ = 21894991 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21896988 and 21897006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21897089) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47269 + ... + 47729.

It is an arithmetic number, because the mean of its divisors is an integer number (1862784).

Almost surely, 2^21897039 is an apocalyptic number.

21897039 is a deficient number, since it is larger than the sum of its proper divisors (7907505).

21897039 is a wasteful number, since it uses less digits than its factorization.

21897039 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 758.

The product of its (nonzero) digits is 27216, while the sum is 39.

The square root of 21897039 is about 4679.4272085374. The cubic root of 21897039 is about 279.7661269884.

The spelling of 21897039 in words is "twenty-one million, eight hundred ninety-seven thousand, thirty-nine".