131221025 has 12 divisors (see below), whose sum is σ = 175230972. Its totient is φ = 96901440.

The previous prime is 131221021. The next prime is 131221037. The reversal of 131221025 is 520122131.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 1784896 + 129436129 = 1336^2 + 11377^2 .

It is not a de Polignac number, because 131221025 - 2² = 131221021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 131220994 and 131221012.

It is not an unprimeable number, because it can be changed into a prime (131221021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 201554 + ... + 202203.

It is an arithmetic number, because the mean of its divisors is an integer number (14602581).

Almost surely, 2^131221025 is an apocalyptic number.

It is an amenable number.

131221025 is a deficient number, since it is larger than the sum of its proper divisors (44009947).

131221025 is a wasteful number, since it uses less digits than its factorization.

131221025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 403780 (or 403775 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 131221025 is about 11455.1745949156. The cubic root of 131221025 is about 508.1607787225.

Adding to 131221025 its reverse (520122131), we get a palindrome (651343156).

The spelling of 131221025 in words is "one hundred thirty-one million, two hundred twenty-one thousand, twenty-five".