31309601 has 4 divisors (see below), whose sum is σ = 32670912. Its totient is φ = 29948292.

The previous prime is 31309583. The next prime is 31309637. The reversal of 31309601 is 10690313.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 10690313 = 2503 ⋅4271.

It is a cyclic number.

It is not a de Polignac number, because 31309601 - 2¹⁴ = 31293217 is a prime.

It is a super-2 number, since 2×31309601² = 1960582229558402, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 1361287 = 31309601 / (3 + 1 + 3 + 0 + 9 + 6 + 0 + 1).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (31309001) 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, 680621 + ... + 680666.

It is an arithmetic number, because the mean of its divisors is an integer number (8167728).

Almost surely, 2^31309601 is an apocalyptic number.

It is an amenable number.

31309601 is a deficient number, since it is larger than the sum of its proper divisors (1361311).

31309601 is a wasteful number, since it uses less digits than its factorization.

31309601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1361310.

The product of its (nonzero) digits is 486, while the sum is 23.

The square root of 31309601 is about 5595.4982798675. The cubic root of 31309601 is about 315.1803821147.

Adding to 31309601 its reverse (10690313), we get a palindrome (41999914).

The spelling of 31309601 in words is "thirty-one million, three hundred nine thousand, six hundred one".