131621820 has 96 divisors (see below), whose sum is σ = 425730816. Its totient is φ = 30028800.

The previous prime is 131621783. The next prime is 131621827. The reversal of 131621820 is 28126131.

It is a super-2 number, since 2×131621820² = 34648607000224800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131621827) 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, 5355 + ... + 17085.

It is an arithmetic number, because the mean of its divisors is an integer number (4434696).

Almost surely, 2^131621820 is an apocalyptic number.

131621820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 131621820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (212865408).

131621820 is an abundant number, since it is smaller than the sum of its proper divisors (294108996).

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

131621820 is a wasteful number, since it uses less digits than its factorization.

131621820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11771 (or 11769 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 131621820 is about 11472.6553160112. The cubic root of 131621820 is about 508.6776199130.

Adding to 131621820 its reverse (28126131), we get a palindrome (159747951).

The spelling of 131621820 in words is "one hundred thirty-one million, six hundred twenty-one thousand, eight hundred twenty".