21722436 has 18 divisors (see below), whose sum is σ = 54909582. Its totient is φ = 7240800.

The previous prime is 21722429. The next prime is 21722483. The reversal of 21722436 is 63422712.

It can be written as a sum of positive squares in only one way, i.e., 21678336 + 44100 = 4656^2 + 210^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 301665 + ... + 301736.

Almost surely, 2^21722436 is an apocalyptic number.

It is an amenable number.

21722436 is an abundant number, since it is smaller than the sum of its proper divisors (33187146).

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

21722436 is a wasteful number, since it uses less digits than its factorization.

21722436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 603411 (or 603406 counting only the distinct ones).

The product of its digits is 4032, while the sum is 27.

The square root of 21722436 is about 4660.7334186799. The cubic root of 21722436 is about 279.0205403616.

The spelling of 21722436 in words is "twenty-one million, seven hundred twenty-two thousand, four hundred thirty-six".