20721954 has 16 divisors (see below), whose sum is σ = 45211680. Its totient is φ = 6279360.

The previous prime is 20721949. The next prime is 20721983. The reversal of 20721954 is 45912702.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 156919 + ... + 157050.

It is an arithmetic number, because the mean of its divisors is an integer number (2825730).

Almost surely, 2^20721954 is an apocalyptic number.

20721954 is an abundant number, since it is smaller than the sum of its proper divisors (24489726).

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

20721954 is a wasteful number, since it uses less digits than its factorization.

20721954 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313985.

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

The square root of 20721954 is about 4552.1373002140. The cubic root of 20721954 is about 274.6693723485.

The spelling of 20721954 in words is "twenty million, seven hundred twenty-one thousand, nine hundred fifty-four".