21532705 has 16 divisors (see below), whose sum is σ = 26703360. Its totient is φ = 16656192.

The previous prime is 21532697. The next prime is 21532717. The reversal of 21532705 is 50723512.

It is a cyclic number.

It is not a de Polignac number, because 21532705 - 2³ = 21532697 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21532705.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43972 + ... + 44458.

It is an arithmetic number, because the mean of its divisors is an integer number (1668960).

Almost surely, 2^21532705 is an apocalyptic number.

It is an amenable number.

21532705 is a deficient number, since it is larger than the sum of its proper divisors (5170655).

21532705 is a wasteful number, since it uses less digits than its factorization.

21532705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 768.

The product of its (nonzero) digits is 2100, while the sum is 25.

The square root of 21532705 is about 4640.3345784544. The cubic root of 21532705 is about 278.2058108820.

The spelling of 21532705 in words is "twenty-one million, five hundred thirty-two thousand, seven hundred five".