18121797 has 6 divisors (see below), whose sum is σ = 26175942. Its totient is φ = 12081192.

The previous prime is 18121787. The next prime is 18121799. The reversal of 18121797 is 79712181.

It can be written as a sum of positive squares in only one way, i.e., 18096516 + 25281 = 4254^2 + 159^2 .

It is not a de Polignac number, because 18121797 - 2¹⁴ = 18105413 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18121799) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1006758 + ... + 1006775.

It is an arithmetic number, because the mean of its divisors is an integer number (4362657).

Almost surely, 2^18121797 is an apocalyptic number.

It is an amenable number.

18121797 is a deficient number, since it is larger than the sum of its proper divisors (8054145).

18121797 is a wasteful number, since it uses less digits than its factorization.

18121797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2013539 (or 2013536 counting only the distinct ones).

The product of its digits is 7056, while the sum is 36.

The square root of 18121797 is about 4256.9704015884. The cubic root of 18121797 is about 262.6639193872.

The spelling of 18121797 in words is "eighteen million, one hundred twenty-one thousand, seven hundred ninety-seven".