21720954 has 8 divisors (see below), whose sum is σ = 43441920. Its totient is φ = 7240316.

The previous prime is 21720953. The next prime is 21720983. The reversal of 21720954 is 45902712.

21720954 is nontrivially palindromic in base 7.

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

21720954 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (21720953) 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, 1810074 + ... + 1810085.

It is an arithmetic number, because the mean of its divisors is an integer number (5430240).

Almost surely, 2^21720954 is an apocalyptic number.

21720954 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21720954 is a wasteful number, since it uses less digits than its factorization.

21720954 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3620164.

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 21720954 is about 4660.5744281151. The cubic root of 21720954 is about 279.0141948816.

The spelling of 21720954 in words is "twenty-one million, seven hundred twenty thousand, nine hundred fifty-four".