51511645 has 4 divisors (see below), whose sum is σ = 61813980. Its totient is φ = 41209312.

The previous prime is 51511643. The next prime is 51511657. The reversal of 51511645 is 54611515.

It is a happy number.

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 17089956 + 34421689 = 4134^2 + 5867^2 .

It is a cyclic number.

It is not a de Polignac number, because 51511645 - 2¹ = 51511643 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51511643) 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, 5151160 + ... + 5151169.

It is an arithmetic number, because the mean of its divisors is an integer number (15453495).

Almost surely, 2^51511645 is an apocalyptic number.

It is an amenable number.

51511645 is a deficient number, since it is larger than the sum of its proper divisors (10302335).

51511645 is a wasteful number, since it uses less digits than its factorization.

51511645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10302334.

The product of its digits is 3000, while the sum is 28.

The square root of 51511645 is about 7177.1613469393. The cubic root of 51511645 is about 372.0789832098.

The spelling of 51511645 in words is "fifty-one million, five hundred eleven thousand, six hundred forty-five".