21220120131 has 16 divisors (see below), whose sum is σ = 32469600768. Its totient is φ = 12075465600.

The previous prime is 21220120123. The next prime is 21220120139. The reversal of 21220120131 is 13102102212.

It is an interprime number because it is at equal distance from previous prime (21220120123) and next prime (21220120139).

It is not a de Polignac number, because 21220120131 - 2³ = 21220120123 is a prime.

It is a super-2 number, since 2×21220120131² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21220120131.

It is not an unprimeable number, because it can be changed into a prime (21220120139) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2091375 + ... + 2101496.

It is an arithmetic number, because the mean of its divisors is an integer number (2029350048).

Almost surely, 2^21220120131 is an apocalyptic number.

21220120131 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21220120131 is a deficient number, since it is larger than the sum of its proper divisors (11249480637).

21220120131 is a wasteful number, since it uses less digits than its factorization.

21220120131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4193122.

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21220120131 its reverse (13102102212), we get a palindrome (34322222343).

The spelling of 21220120131 in words is "twenty-one billion, two hundred twenty million, one hundred twenty thousand, one hundred thirty-one".