51111565 has 4 divisors (see below), whose sum is σ = 61333884. Its totient is φ = 40889248.

The previous prime is 51111559. The next prime is 51111581. The reversal of 51111565 is 56511115.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18003049 + 33108516 = 4243^2 + 5754^2 .

It is a cyclic number.

It is not a de Polignac number, because 51111565 - 2¹³ = 51103373 is a prime.

It is a super-2 number, since 2×51111565² = 5224784153498450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5111152 + ... + 5111161.

It is an arithmetic number, because the mean of its divisors is an integer number (15333471).

Almost surely, 2^51111565 is an apocalyptic number.

It is an amenable number.

51111565 is a deficient number, since it is larger than the sum of its proper divisors (10222319).

51111565 is a wasteful number, since it uses less digits than its factorization.

51111565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10222318.

The product of its digits is 750, while the sum is 25.

The square root of 51111565 is about 7149.2352737898. The cubic root of 51111565 is about 371.1131923826.

The spelling of 51111565 in words is "fifty-one million, one hundred eleven thousand, five hundred sixty-five".