21755324 has 6 divisors (see below), whose sum is σ = 38071824. Its totient is φ = 10877660.

The previous prime is 21755267. The next prime is 21755329. The reversal of 21755324 is 42355712.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21755329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2719412 + ... + 2719419.

It is an arithmetic number, because the mean of its divisors is an integer number (6345304).

Almost surely, 2^21755324 is an apocalyptic number.

It is an amenable number.

21755324 is a deficient number, since it is larger than the sum of its proper divisors (16316500).

21755324 is a wasteful number, since it uses less digits than its factorization.

21755324 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5438835 (or 5438833 counting only the distinct ones).

The product of its digits is 8400, while the sum is 29.

The square root of 21755324 is about 4664.2602843323. The cubic root of 21755324 is about 279.1612827159.

The spelling of 21755324 in words is "twenty-one million, seven hundred fifty-five thousand, three hundred twenty-four".