61431309 has 12 divisors (see below), whose sum is σ = 91794300. Its totient is φ = 39541824.

The previous prime is 61431301. The next prime is 61431341. The reversal of 61431309 is 90313416.

It can be written as a sum of positive squares in 2 ways, for example, as 51883209 + 9548100 = 7203^2 + 3090^2 .

It is not a de Polignac number, because 61431309 - 2³ = 61431301 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61431301) 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, 117424 + ... + 117945.

It is an arithmetic number, because the mean of its divisors is an integer number (7649525).

Almost surely, 2^61431309 is an apocalyptic number.

It is an amenable number.

61431309 is a deficient number, since it is larger than the sum of its proper divisors (30362991).

61431309 is a wasteful number, since it uses less digits than its factorization.

61431309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235404 (or 235401 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 27.

The square root of 61431309 is about 7837.8127688788. The cubic root of 61431309 is about 394.5753252437.

The spelling of 61431309 in words is "sixty-one million, four hundred thirty-one thousand, three hundred nine".