52515781 has 4 divisors (see below), whose sum is σ = 54326700. Its totient is φ = 50704864.

The previous prime is 52515773. The next prime is 52515787. The reversal of 52515781 is 18751525.

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 13653025 + 38862756 = 3695^2 + 6234^2 .

It is a cyclic number.

It is not a de Polignac number, because 52515781 - 2³ = 52515773 is a prime.

It is a super-2 number, since 2×52515781² = 5515814508079922, 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 (52515787) 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, 905416 + ... + 905473.

It is an arithmetic number, because the mean of its divisors is an integer number (13581675).

Almost surely, 2^52515781 is an apocalyptic number.

It is an amenable number.

52515781 is a deficient number, since it is larger than the sum of its proper divisors (1810919).

52515781 is a wasteful number, since it uses less digits than its factorization.

52515781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1810918.

The product of its digits is 14000, while the sum is 34.

The square root of 52515781 is about 7246.7772837310. Note that the first 3 decimals coincide. The cubic root of 52515781 is about 374.4811336643.

The spelling of 52515781 in words is "fifty-two million, five hundred fifteen thousand, seven hundred eighty-one".