21122736 has 40 divisors (see below), whose sum is σ = 55119984. Its totient is φ = 6969600.

The previous prime is 21122719. The next prime is 21122743. The reversal of 21122736 is 63722112.

It is a super-2 number, since 2×21122736² = 892339952251392, which contains 22 as substring.

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

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, 2670 + ... + 7026.

Almost surely, 2^21122736 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21122736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27559992).

21122736 is an abundant number, since it is smaller than the sum of its proper divisors (33997248).

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

21122736 is a wasteful number, since it uses less digits than its factorization.

21122736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4469 (or 4463 counting only the distinct ones).

The product of its digits is 1008, while the sum is 24.

The square root of 21122736 is about 4595.9477803822. The cubic root of 21122736 is about 276.4288648706.

Adding to 21122736 its reverse (63722112), we get a palindrome (84844848).

The spelling of 21122736 in words is "twenty-one million, one hundred twenty-two thousand, seven hundred thirty-six".