21534645 has 16 divisors (see below), whose sum is σ = 37588032. Its totient is φ = 10440960.

The previous prime is 21534577. The next prime is 21534659. The reversal of 21534645 is 54643512.

It is not a de Polignac number, because 21534645 - 2⁷ = 21534517 is a prime.

It is a congruent number.

It is an unprimeable number.

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, 65092 + ... + 65421.

It is an arithmetic number, because the mean of its divisors is an integer number (2349252).

Almost surely, 2^21534645 is an apocalyptic number.

It is an amenable number.

21534645 is a deficient number, since it is larger than the sum of its proper divisors (16053387).

21534645 is a wasteful number, since it uses less digits than its factorization.

21534645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130532.

The product of its digits is 14400, while the sum is 30.

The square root of 21534645 is about 4640.5436103974. The cubic root of 21534645 is about 278.2141656624.

The spelling of 21534645 in words is "twenty-one million, five hundred thirty-four thousand, six hundred forty-five".