20121797790 has 32 divisors (see below), whose sum is σ = 53658128160. Its totient is φ = 5365812672.

The previous prime is 20121797777. The next prime is 20121797833. The reversal of 20121797790 is 9779712102.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37262319 + ... + 37262858.

It is an arithmetic number, because the mean of its divisors is an integer number (1676816505).

Almost surely, 2^20121797790 is an apocalyptic number.

20121797790 is an abundant number, since it is smaller than the sum of its proper divisors (33536330370).

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

20121797790 is a wasteful number, since it uses less digits than its factorization.

20121797790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74525193 (or 74525187 counting only the distinct ones).

The product of its (nonzero) digits is 111132, while the sum is 45.

The spelling of 20121797790 in words is "twenty billion, one hundred twenty-one million, seven hundred ninety-seven thousand, seven hundred ninety".