22721557 has 8 divisors (see below), whose sum is σ = 23123232. Its totient is φ = 22323600.

The previous prime is 22721507. The next prime is 22721563. The reversal of 22721557 is 75512722.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 22721557 - 2¹⁵ = 22688789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22721507) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13207 + ... + 14827.

It is an arithmetic number, because the mean of its divisors is an integer number (2890404).

Almost surely, 2^22721557 is an apocalyptic number.

It is an amenable number.

22721557 is a deficient number, since it is larger than the sum of its proper divisors (401675).

22721557 is a wasteful number, since it uses less digits than its factorization.

22721557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1859.

The product of its digits is 9800, while the sum is 31.

The square root of 22721557 is about 4766.7134379990. The cubic root of 22721557 is about 283.2344197594.

The spelling of 22721557 in words is "twenty-two million, seven hundred twenty-one thousand, five hundred fifty-seven".