21956601 has 4 divisors (see below), whose sum is σ = 29275472. Its totient is φ = 14637732.

The previous prime is 21956591. The next prime is 21956603. The reversal of 21956601 is 10665912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21956601 - 2⁹ = 21956089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21956603) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3659431 + ... + 3659436.

It is an arithmetic number, because the mean of its divisors is an integer number (7318868).

Almost surely, 2^21956601 is an apocalyptic number.

It is an amenable number.

21956601 is a deficient number, since it is larger than the sum of its proper divisors (7318871).

21956601 is an equidigital number, since it uses as much as digits as its factorization.

21956601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7318870.

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 21956601 is about 4685.7871270471. The cubic root of 21956601 is about 280.0195607083.

The spelling of 21956601 in words is "twenty-one million, nine hundred fifty-six thousand, six hundred one".