20013121620 has 72 divisors (see below), whose sum is σ = 60978817536. Its totient is φ = 5312889792.

The previous prime is 20013121567. The next prime is 20013121637. The reversal of 20013121620 is 2612131002.

20013121620 is a `hidden beast` number, since 20 + 0 + 1 + 3 + 1 + 21 + 620 = 666.

It is a super-2 number, since 2×20013121620² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 20013121593 and 20013121602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 209152 + ... + 289431.

Almost surely, 2^20013121620 is an apocalyptic number.

20013121620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20013121620 is an abundant number, since it is smaller than the sum of its proper divisors (40965695916).

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

20013121620 is a wasteful number, since it uses less digits than its factorization.

20013121620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 498821 (or 498816 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 20013121620 its reverse (2612131002), we get a palindrome (22625252622).

The spelling of 20013121620 in words is "twenty billion, thirteen million, one hundred twenty-one thousand, six hundred twenty".