20003121990 has 64 divisors (see below), whose sum is σ = 53407065600. Its totient is φ = 5327625312.

The previous prime is 20003121977. The next prime is 20003121991. The reversal of 20003121990 is 9912130002.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20003121991) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 177201 + ... + 267219.

It is an arithmetic number, because the mean of its divisors is an integer number (834485400).

Almost surely, 2^20003121990 is an apocalyptic number.

20003121990 is an abundant number, since it is smaller than the sum of its proper divisors (33403943610).

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

20003121990 is a wasteful number, since it uses less digits than its factorization.

20003121990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90858 (or 90852 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

Adding to 20003121990 its reverse (9912130002), we get a palindrome (29915251992).

The spelling of 20003121990 in words is "twenty billion, three million, one hundred twenty-one thousand, nine hundred ninety".