131821840 has 40 divisors (see below), whose sum is σ = 313015680. Its totient is φ = 51605376.

The previous prime is 131821831. The next prime is 131821841. The reversal of 131821840 is 48128131.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 131821799 and 131821808.

It is not an unprimeable number, because it can be changed into a prime (131821841) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13770 + ... + 21289.

It is an arithmetic number, because the mean of its divisors is an integer number (7825392).

Almost surely, 2^131821840 is an apocalyptic number.

131821840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

131821840 is an abundant number, since it is smaller than the sum of its proper divisors (181193840).

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

131821840 is a wasteful number, since it uses less digits than its factorization.

131821840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35119 (or 35113 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 131821840 is about 11481.3692563213. The cubic root of 131821840 is about 508.9351613082.

Adding to 131821840 its reverse (48128131), we get a palindrome (179949971).

The spelling of 131821840 in words is "one hundred thirty-one million, eight hundred twenty-one thousand, eight hundred forty".