561951 has 16 divisors (see below), whose sum is σ = 897120. Its totient is φ = 345600.

The previous prime is 561947. The next prime is 561961. The reversal of 561951 is 159165.

561951 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 561951 - 2² = 561947 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

561951 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561931) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 450 + ... + 1151.

It is an arithmetic number, because the mean of its divisors is an integer number (56070).

2⁵⁶¹⁹⁵¹ is an apocalyptic number.

561951 is a deficient number, since it is larger than the sum of its proper divisors (335169).

561951 is a wasteful number, since it uses less digits than its factorization.

561951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1623 (or 1617 counting only the distinct ones).

The product of its digits is 1350, while the sum is 27.

The square root of 561951 is about 749.6339106524. The cubic root of 561951 is about 82.5213168056.

The spelling of 561951 in words is "five hundred sixty-one thousand, nine hundred fifty-one".