561781031 has 18 divisors (see below), whose sum is σ = 694220328. Its totient is φ = 453190080.

The previous prime is 561781019. The next prime is 561781061. The reversal of 561781031 is 130187165.

It is not a de Polignac number, because 561781031 - 2¹⁸ = 561518887 is a prime.

It is a super-2 number, since 2×561781031² = 631195853582845922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561781001) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 5675 + ... + 33996.

It is an arithmetic number, because the mean of its divisors is an integer number (38567796).

Almost surely, 2^561781031 is an apocalyptic number.

561781031 is a deficient number, since it is larger than the sum of its proper divisors (132439297).

561781031 is a wasteful number, since it uses less digits than its factorization.

561781031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39719 (or 39695 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 561781031 is about 23701.9204074269. The cubic root of 561781031 is about 825.1299610384.

The spelling of 561781031 in words is "five hundred sixty-one million, seven hundred eighty-one thousand, thirty-one".