51515749 has 2 divisors, whose sum is σ = 51515750. Its totient is φ = 51515748.

The previous prime is 51515747. The next prime is 51515771. The reversal of 51515749 is 94751515.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 38663524 + 12852225 = 6218^2 + 3585^2 .

It is a cyclic number.

It is not a de Polignac number, because 51515749 - 2¹ = 51515747 is a prime.

Together with 51515747, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51515741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25757874 + 25757875.

It is an arithmetic number, because the mean of its divisors is an integer number (25757875).

Almost surely, 2^51515749 is an apocalyptic number.

It is an amenable number.

51515749 is a deficient number, since it is larger than the sum of its proper divisors (1).

51515749 is an equidigital number, since it uses as much as digits as its factorization.

51515749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31500, while the sum is 37.

The square root of 51515749 is about 7177.4472481517. The cubic root of 51515749 is about 372.0888642868.

The spelling of 51515749 in words is "fifty-one million, five hundred fifteen thousand, seven hundred forty-nine".