21389995 has 16 divisors (see below), whose sum is σ = 29649888. Its totient is φ = 14640640.

The previous prime is 21389971. The next prime is 21389999. The reversal of 21389995 is 59998312.

It is not a de Polignac number, because 21389995 - 2⁹ = 21389483 is a prime.

It is a super-2 number, since 2×21389995² = 915063772200050, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21389999) 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, 10504 + ... + 12373.

It is an arithmetic number, because the mean of its divisors is an integer number (1853118).

Almost surely, 2^21389995 is an apocalyptic number.

21389995 is a deficient number, since it is larger than the sum of its proper divisors (8259893).

21389995 is a wasteful number, since it uses less digits than its factorization.

21389995 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22910.

The product of its digits is 174960, while the sum is 46.

The square root of 21389995 is about 4624.9318913904. The cubic root of 21389995 is about 277.5898364549.

The spelling of 21389995 in words is "twenty-one million, three hundred eighty-nine thousand, nine hundred ninety-five".