18220957 has 4 divisors (see below), whose sum is σ = 19292796. Its totient is φ = 17149120.

The previous prime is 18220927. The next prime is 18220967. The reversal of 18220957 is 75902281.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13645636 + 4575321 = 3694^2 + 2139^2 .

It is a cyclic number.

It is not a de Polignac number, because 18220957 - 2¹⁵ = 18188189 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 (18220927) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 535894 + ... + 535927.

It is an arithmetic number, because the mean of its divisors is an integer number (4823199).

Almost surely, 2^18220957 is an apocalyptic number.

18220957 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

18220957 is a deficient number, since it is larger than the sum of its proper divisors (1071839).

18220957 is a wasteful number, since it uses less digits than its factorization.

18220957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1071838.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 18220957 is about 4268.6012931638. The cubic root of 18220957 is about 263.1421352408.

The spelling of 18220957 in words is "eighteen million, two hundred twenty thousand, nine hundred fifty-seven".