21712775 has 24 divisors (see below), whose sum is σ = 31364064. Its totient is φ = 14601600.

The previous prime is 21712753. The next prime is 21712781. The reversal of 21712775 is 57721712.

It is not a de Polignac number, because 21712775 - 2¹⁴ = 21696391 is a prime.

It is a Duffinian 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, 8105 + ... + 10445.

It is an arithmetic number, because the mean of its divisors is an integer number (1306836).

Almost surely, 2^21712775 is an apocalyptic number.

21712775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21712775 is a deficient number, since it is larger than the sum of its proper divisors (9651289).

21712775 is a wasteful number, since it uses less digits than its factorization.

21712775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2411 (or 2406 counting only the distinct ones).

The product of its digits is 6860, while the sum is 32.

The square root of 21712775 is about 4659.6968785534. The cubic root of 21712775 is about 278.9791696614.

The spelling of 21712775 in words is "twenty-one million, seven hundred twelve thousand, seven hundred seventy-five".