18720157 has 8 divisors (see below), whose sum is σ = 18948600. Its totient is φ = 18493440.

The previous prime is 18720083. The next prime is 18720173. The reversal of 18720157 is 75102781.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 10023556 + 8696601 = 3166^2 + 2949^2 .

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 18720157 - 2¹⁹ = 18195869 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 (18720197) 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, 41469 + ... + 41917.

It is an arithmetic number, because the mean of its divisors is an integer number (2368575).

Almost surely, 2^18720157 is an apocalyptic number.

It is an amenable number.

18720157 is a deficient number, since it is larger than the sum of its proper divisors (228443).

18720157 is a wasteful number, since it uses less digits than its factorization.

18720157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 863.

The product of its (nonzero) digits is 3920, while the sum is 31.

The square root of 18720157 is about 4326.6796738377. The cubic root of 18720157 is about 265.5236211418.

The spelling of 18720157 in words is "eighteen million, seven hundred twenty thousand, one hundred fifty-seven".