21530727 has 6 divisors (see below), whose sum is σ = 31099952. Its totient is φ = 14353812.

The previous prime is 21530713. The next prime is 21530741. The reversal of 21530727 is 72703512.

It is an interprime number because it is at equal distance from previous prime (21530713) and next prime (21530741).

It is not a de Polignac number, because 21530727 - 2⁴ = 21530711 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21530727.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21530777) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1196143 + ... + 1196160.

Almost surely, 2^21530727 is an apocalyptic number.

21530727 is a deficient number, since it is larger than the sum of its proper divisors (9569225).

21530727 is a wasteful number, since it uses less digits than its factorization.

21530727 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2392309 (or 2392306 counting only the distinct ones).

The product of its (nonzero) digits is 2940, while the sum is 27.

The square root of 21530727 is about 4640.1214423763. The cubic root of 21530727 is about 278.1972919346.

The spelling of 21530727 in words is "twenty-one million, five hundred thirty thousand, seven hundred twenty-seven".