19779989400900 has 81 divisors (see below), whose sum is σ = 61999696102071. Its totient is φ = 5274628260480.

The previous prime is 19779989400827. The next prime is 19779989400901. The reversal of 19779989400900 is 900498997791.

The square root of 19779989400900 is 4447470.

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

It can be written as a sum of positive squares in 4 ways, for example, as 3268639811844 + 16511349589056 = 1807938^2 + 4063416^2 .

It is not an unprimeable number, because it can be changed into a prime (19779989400901) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 133349976 + ... + 133498224.

Almost surely, 2^{19779989400900} is an apocalyptic number.

19779989400900 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19779989400900 is the 4447470-th square number.

It is an amenable number.

19779989400900 is an abundant number, since it is smaller than the sum of its proper divisors (42219706701171).

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

19779989400900 is an frugal number, since it uses more digits than its factorization.

19779989400900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 296518 (or 148259 counting only the distinct ones).

The product of its (nonzero) digits is 92588832, while the sum is 72.

The spelling of 19779989400900 in words is "nineteen trillion, seven hundred seventy-nine billion, nine hundred eighty-nine million, four hundred thousand, nine hundred".