21722424 has 32 divisors (see below), whose sum is σ = 54516240. Its totient is φ = 7212800.

The previous prime is 21722423. The next prime is 21722429. The reversal of 21722424 is 42422712.

It is a hoax number, since the sum of its digits (24) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a junction number, because it is equal to n+sod(n) for n = 21722394 and 21722403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21722423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5134 + ... + 8354.

Almost surely, 2^21722424 is an apocalyptic number.

21722424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21722424 is an abundant number, since it is smaller than the sum of its proper divisors (32793816).

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

21722424 is a wasteful number, since it uses less digits than its factorization.

21722424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3511 (or 3507 counting only the distinct ones).

The product of its digits is 1792, while the sum is 24.

The square root of 21722424 is about 4660.7321313287. The cubic root of 21722424 is about 279.0204889823.

The spelling of 21722424 in words is "twenty-one million, seven hundred twenty-two thousand, four hundred twenty-four".