21905532 has 48 divisors (see below), whose sum is σ = 61958400. Its totient is φ = 6637680.

The previous prime is 21905531. The next prime is 21905573. The reversal of 21905532 is 23550912.

21905532 is a `hidden beast` number, since 21 + 90 + 553 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 21905496 and 21905505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21905531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8032 + ... + 10407.

It is an arithmetic number, because the mean of its divisors is an integer number (1290800).

Almost surely, 2^21905532 is an apocalyptic number.

21905532 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21905532 is an abundant number, since it is smaller than the sum of its proper divisors (40052868).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21905532 is a wasteful number, since it uses less digits than its factorization.

21905532 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18463 (or 18455 counting only the distinct ones).

The product of its (nonzero) digits is 2700, while the sum is 27.

The square root of 21905532 is about 4680.3346034231. The cubic root of 21905532 is about 279.8022924046.

The spelling of 21905532 in words is "twenty-one million, nine hundred five thousand, five hundred thirty-two".