18943690 has 8 divisors (see below), whose sum is σ = 34098660. Its totient is φ = 7577472.

The previous prime is 18943669. The next prime is 18943747. The reversal of 18943690 is 9634981.

It can be written as a sum of positive squares in 2 ways, for example, as 18139081 + 804609 = 4259^2 + 897^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×18943690² = 717726781632200, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 947175 + ... + 947194.

Almost surely, 2^18943690 is an apocalyptic number.

18943690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18943690 is a deficient number, since it is larger than the sum of its proper divisors (15154970).

18943690 is a wasteful number, since it uses less digits than its factorization.

18943690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1894376.

The product of its (nonzero) digits is 46656, while the sum is 40.

The square root of 18943690 is about 4352.4349506914. The cubic root of 18943690 is about 266.5762940292.

The spelling of 18943690 in words is "eighteen million, nine hundred forty-three thousand, six hundred ninety".