21089995 has 16 divisors (see below), whose sum is σ = 26069472. Its totient is φ = 16369920.

The previous prime is 21089993. The next prime is 21090007. The reversal of 21089995 is 59998012.

It is not a de Polignac number, because 21089995 - 2¹ = 21089993 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21089993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49885 + ... + 50305.

It is an arithmetic number, because the mean of its divisors is an integer number (1629342).

Almost surely, 2^21089995 is an apocalyptic number.

21089995 is a deficient number, since it is larger than the sum of its proper divisors (4979477).

21089995 is a wasteful number, since it uses less digits than its factorization.

21089995 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 702.

The product of its (nonzero) digits is 58320, while the sum is 43.

The square root of 21089995 is about 4592.3844569025. The cubic root of 21089995 is about 276.2859661204.

The spelling of 21089995 in words is "twenty-one million, eighty-nine thousand, nine hundred ninety-five".