18121772 has 6 divisors (see below), whose sum is σ = 31713108. Its totient is φ = 9060884.

The previous prime is 18121771. The next prime is 18121777. The reversal of 18121772 is 27712181.

It is not an unprimeable number, because it can be changed into a prime (18121771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2265218 + ... + 2265225.

It is an arithmetic number, because the mean of its divisors is an integer number (5285518).

Almost surely, 2^18121772 is an apocalyptic number.

It is an amenable number.

18121772 is a deficient number, since it is larger than the sum of its proper divisors (13591336).

18121772 is a wasteful number, since it uses less digits than its factorization.

18121772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4530447 (or 4530445 counting only the distinct ones).

The product of its digits is 1568, while the sum is 29.

The square root of 18121772 is about 4256.9674652269. The cubic root of 18121772 is about 262.6637986007.

The spelling of 18121772 in words is "eighteen million, one hundred twenty-one thousand, seven hundred seventy-two".