18722457 has 24 divisors (see below), whose sum is σ = 30840264. Its totient is φ = 10842624.

The previous prime is 18722449. The next prime is 18722461. The reversal of 18722457 is 75422781.

18722457 is a `hidden beast` number, since 187 + 22 + 457 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 8088336 + 10634121 = 2844^2 + 3261^2 .

It is not a de Polignac number, because 18722457 - 2³ = 18722449 is a prime.

It is a super-2 number, since 2×18722457² = 701060792233698, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18721457) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2718 + ... + 6695.

It is an arithmetic number, because the mean of its divisors is an integer number (1285011).

Almost surely, 2^18722457 is an apocalyptic number.

18722457 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

18722457 is a deficient number, since it is larger than the sum of its proper divisors (12117807).

18722457 is a wasteful number, since it uses less digits than its factorization.

18722457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9449 (or 9446 counting only the distinct ones).

The product of its digits is 31360, while the sum is 36.

The square root of 18722457 is about 4326.9454584037. The cubic root of 18722457 is about 265.5344949701.

The spelling of 18722457 in words is "eighteen million, seven hundred twenty-two thousand, four hundred fifty-seven".