22721040 has 160 divisors (see below), whose sum is σ = 79935360. Its totient is φ = 5930496.

The previous prime is 22721029. The next prime is 22721051. The reversal of 22721040 is 4012722.

It is an interprime number because it is at equal distance from previous prime (22721029) and next prime (22721051).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 144642 + ... + 144798.

It is an arithmetic number, because the mean of its divisors is an integer number (499596).

Almost surely, 2^22721040 is an apocalyptic number.

22721040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

22721040 is the 3015-th heptagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 22721040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39967680).

22721040 is an abundant number, since it is smaller than the sum of its proper divisors (57214320).

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

22721040 is a wasteful number, since it uses less digits than its factorization.

22721040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246 (or 234 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 22721040 is about 4766.6592074534. The cubic root of 22721040 is about 283.2322715307.

Adding to 22721040 its reverse (4012722), we get a palindrome (26733762).

The spelling of 22721040 in words is "twenty-two million, seven hundred twenty-one thousand, forty".