31061561 has 4 divisors (see below), whose sum is σ = 32696400. Its totient is φ = 29426724.

The previous prime is 31061543. The next prime is 31061579. The reversal of 31061561 is 16516013.

It is a happy number.

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.

It is an interprime number because it is at equal distance from previous prime (31061543) and next prime (31061579).

It is a cyclic number.

It is not a de Polignac number, because 31061561 - 2⁶ = 31061497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31061461) 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, 817391 + ... + 817428.

It is an arithmetic number, because the mean of its divisors is an integer number (8174100).

Almost surely, 2^31061561 is an apocalyptic number.

It is an amenable number.

31061561 is a deficient number, since it is larger than the sum of its proper divisors (1634839).

31061561 is a wasteful number, since it uses less digits than its factorization.

31061561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1634838.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 31061561 is about 5573.2899619525. The cubic root of 31061561 is about 314.3458702541.

Adding to 31061561 its reverse (16516013), we get a palindrome (47577574).

The spelling of 31061561 in words is "thirty-one million, sixty-one thousand, five hundred sixty-one".