21932561 has 8 divisors (see below), whose sum is σ = 25104960. Its totient is φ = 18769968.

The previous prime is 21932557. The next prime is 21932569. The reversal of 21932561 is 16523912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21932561 - 2² = 21932557 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21932569) 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 7 ways as a sum of consecutive naturals, for example, 3230 + ... + 7368.

It is an arithmetic number, because the mean of its divisors is an integer number (3138120).

Almost surely, 2^21932561 is an apocalyptic number.

It is an amenable number.

21932561 is a deficient number, since it is larger than the sum of its proper divisors (3172399).

21932561 is an equidigital number, since it uses as much as digits as its factorization.

21932561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4903.

The product of its digits is 3240, while the sum is 29.

The square root of 21932561 is about 4683.2212204849. The cubic root of 21932561 is about 279.9173267827.

The spelling of 21932561 in words is "twenty-one million, nine hundred thirty-two thousand, five hundred sixty-one".