51569661 has 16 divisors (see below), whose sum is σ = 80781120. Its totient is φ = 28849920.

The previous prime is 51569659. The next prime is 51569663. The reversal of 51569661 is 16696515.

It is an interprime number because it is at equal distance from previous prime (51569659) and next prime (51569663).

It is not a de Polignac number, because 51569661 - 2¹ = 51569659 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51569663) 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, 59676 + ... + 60533.

It is an arithmetic number, because the mean of its divisors is an integer number (5048820).

Almost surely, 2^51569661 is an apocalyptic number.

It is an amenable number.

51569661 is a deficient number, since it is larger than the sum of its proper divisors (29211459).

51569661 is a wasteful number, since it uses less digits than its factorization.

51569661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120236.

The product of its digits is 48600, while the sum is 39.

The square root of 51569661 is about 7181.2019188991. The cubic root of 51569661 is about 372.2186178838.

The spelling of 51569661 in words is "fifty-one million, five hundred sixty-nine thousand, six hundred sixty-one".