31252561 has 4 divisors (see below), whose sum is σ = 32611392. Its totient is φ = 29893732.

The previous prime is 31252513. The next prime is 31252583. The reversal of 31252561 is 16525213.

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: 16525213 = 983 ⋅16811.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31252561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31252591) 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, 679381 + ... + 679426.

It is an arithmetic number, because the mean of its divisors is an integer number (8152848).

Almost surely, 2^31252561 is an apocalyptic number.

It is an amenable number.

31252561 is a deficient number, since it is larger than the sum of its proper divisors (1358831).

31252561 is a wasteful number, since it uses less digits than its factorization.

31252561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1358830.

The product of its digits is 1800, while the sum is 25.

The square root of 31252561 is about 5590.3990018602. The cubic root of 31252561 is about 314.9888666595.

Adding to 31252561 its reverse (16525213), we get a palindrome (47777774).

It can be divided in two parts, 31252 and 561, that added together give a palindrome (31813).

The spelling of 31252561 in words is "thirty-one million, two hundred fifty-two thousand, five hundred sixty-one".