131431021 has 4 divisors (see below), whose sum is σ = 131537500. Its totient is φ = 131324544.

The previous prime is 131430991. The next prime is 131431031. The reversal of 131431021 is 120134131.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 97732996 + 33698025 = 9886^2 + 5805^2 .

It is a cyclic number.

It is not a de Polignac number, because 131431021 - 2¹⁹ = 130906733 is a prime.

It is a super-2 number, since 2×131431021² = 34548226562204882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 131430986 and 131431004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131431031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51366 + ... + 53863.

It is an arithmetic number, because the mean of its divisors is an integer number (32884375).

Almost surely, 2^131431021 is an apocalyptic number.

It is an amenable number.

131431021 is a deficient number, since it is larger than the sum of its proper divisors (106479).

131431021 is a wasteful number, since it uses less digits than its factorization.

131431021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106478.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 131431021 is about 11464.3369193338. The cubic root of 131431021 is about 508.4317080116.

Adding to 131431021 its reverse (120134131), we get a palindrome (251565152).

The spelling of 131431021 in words is "one hundred thirty-one million, four hundred thirty-one thousand, twenty-one".