18899815807 has 4 divisors (see below), whose sum is σ = 20011569696. Its totient is φ = 17788061920.

The previous prime is 18899815699. The next prime is 18899815853. The reversal of 18899815807 is 70851899881.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18899815807 - 2¹⁹ = 18899291519 is a prime.

It is a super-2 number, since 2×18899815807² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18899815877) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 555876919 + ... + 555876952.

It is an arithmetic number, because the mean of its divisors is an integer number (5002892424).

Almost surely, 2^18899815807 is an apocalyptic number.

18899815807 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

18899815807 is a deficient number, since it is larger than the sum of its proper divisors (1111753889).

18899815807 is a wasteful number, since it uses less digits than its factorization.

18899815807 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1111753888.

The product of its (nonzero) digits is 11612160, while the sum is 64.

The spelling of 18899815807 in words is "eighteen billion, eight hundred ninety-nine million, eight hundred fifteen thousand, eight hundred seven".