131721507 has 6 divisors (see below), whose sum is σ = 190264412. Its totient is φ = 87814332.

The previous prime is 131721497. The next prime is 131721521. The reversal of 131721507 is 705127131.

It is a happy number.

131721507 is a `hidden beast` number, since 131 + 7 + 21 + 507 = 666.

It is not a de Polignac number, because 131721507 - 2¹⁹ = 131197219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (131720507) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7317853 + ... + 7317870.

Almost surely, 2^131721507 is an apocalyptic number.

131721507 is a deficient number, since it is larger than the sum of its proper divisors (58542905).

131721507 is a wasteful number, since it uses less digits than its factorization.

131721507 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14635729 (or 14635726 counting only the distinct ones).

The product of its (nonzero) digits is 1470, while the sum is 27.

The square root of 131721507 is about 11476.9990415613. Note that the first 3 decimals coincide. The cubic root of 131721507 is about 508.8060073123.

Adding to 131721507 its reverse (705127131), we get a palindrome (836848638).

The spelling of 131721507 in words is "one hundred thirty-one million, seven hundred twenty-one thousand, five hundred seven".