21095685 has 24 divisors (see below), whose sum is σ = 39379704. Its totient is φ = 10385280.

The previous prime is 21095677. The next prime is 21095693. The reversal of 21095685 is 58659012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21095677) and next prime (21095693).

It can be written as a sum of positive squares in 4 ways, for example, as 36 + 21095649 = 6^2 + 4593^2 .

It is not a de Polignac number, because 21095685 - 2³ = 21095677 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17446 + ... + 18615.

It is an arithmetic number, because the mean of its divisors is an integer number (1640821).

Almost surely, 2^21095685 is an apocalyptic number.

It is an amenable number.

21095685 is a deficient number, since it is larger than the sum of its proper divisors (18284019).

21095685 is a wasteful number, since it uses less digits than its factorization.

21095685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36085 (or 36082 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 36.

The square root of 21095685 is about 4593.0039190055. The cubic root of 21095685 is about 276.3108108519.

Subtracting from 21095685 its sum of digits (36), we obtain a square (21095649 = 4593²).

The spelling of 21095685 in words is "twenty-one million, ninety-five thousand, six hundred eighty-five".