51115515 has 32 divisors (see below), whose sum is σ = 94473216. Its totient is φ = 23324160.

The previous prime is 51115513. The next prime is 51115523. The reversal of 51115515 is 51551115.

It is not a de Polignac number, because 51115515 - 2¹ = 51115513 is a prime.

It is a super-2 number, since 2×51115515² = 5225591747430450, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (51115511) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6307 + ... + 11916.

It is an arithmetic number, because the mean of its divisors is an integer number (2952288).

Almost surely, 2^51115515 is an apocalyptic number.

51115515 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

51115515 is a deficient number, since it is larger than the sum of its proper divisors (43357701).

51115515 is a wasteful number, since it uses less digits than its factorization.

51115515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18259.

The product of its digits is 625, while the sum is 24.

The square root of 51115515 is about 7149.5115217755. The cubic root of 51115515 is about 371.1227522500.

Subtracting 51115515 from its reverse (51551115), we obtain a square (435600 = 660²).

The spelling of 51115515 in words is "fifty-one million, one hundred fifteen thousand, five hundred fifteen".