20991069900 has 108 divisors (see below), whose sum is σ = 66874129504. Its totient is φ = 5505840000.

The previous prime is 20991069877. The next prime is 20991069901. The reversal of 20991069900 is 996019902.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (20991069901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 136276 + ... + 246075.

Almost surely, 2^20991069900 is an apocalyptic number.

20991069900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20991069900 is an abundant number, since it is smaller than the sum of its proper divisors (45883059604).

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

20991069900 is a wasteful number, since it uses less digits than its factorization.

20991069900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 382432 (or 382422 counting only the distinct ones).

The product of its (nonzero) digits is 78732, while the sum is 45.

The spelling of 20991069900 in words is "twenty billion, nine hundred ninety-one million, sixty-nine thousand, nine hundred".