18361720 has 32 divisors (see below), whose sum is σ = 44493120. Its totient is φ = 6779520.

The previous prime is 18361697. The next prime is 18361723. The reversal of 18361720 is 2716381.

It is a super-2 number, since 2×18361720² = 674305522716800, which contains 22 as substring.

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18361723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17136 + ... + 18175.

It is an arithmetic number, because the mean of its divisors is an integer number (1390410).

Almost surely, 2^18361720 is an apocalyptic number.

18361720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18361720 is an abundant number, since it is smaller than the sum of its proper divisors (26131400).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18361720 is a wasteful number, since it uses less digits than its factorization.

18361720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35335 (or 35331 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 18361720 is about 4285.0577592373. The cubic root of 18361720 is about 263.8180181409.

The spelling of 18361720 in words is "eighteen million, three hundred sixty-one thousand, seven hundred twenty".