18697280644 has 27 divisors (see below), whose sum is σ = 38066218743. Its totient is φ = 8012299848.

The previous prime is 18697280639. The next prime is 18697280647. The reversal of 18697280644 is 44608279681.

It is a happy number.

The square root of 18697280644 is 136738.

It is a perfect power (a square), and thus also a powerful number.

It is not an unprimeable number, because it can be changed into a prime (18697280647) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1909449 + ... + 1919215.

Almost surely, 2^18697280644 is an apocalyptic number.

18697280644 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

18697280644 is the 136738-th square number.

It is an amenable number.

18697280644 is an abundant number, since it is smaller than the sum of its proper divisors (19368938099).

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

18697280644 is an frugal number, since it uses more digits than its factorization.

18697280644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19552 (or 9776 counting only the distinct ones).

The product of its (nonzero) digits is 4644864, while the sum is 55.

The spelling of 18697280644 in words is "eighteen billion, six hundred ninety-seven million, two hundred eighty thousand, six hundred forty-four".