51100661 has 2 divisors, whose sum is σ = 51100662. Its totient is φ = 51100660.

The previous prime is 51100631. The next prime is 51100729. The reversal of 51100661 is 16600115.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47748100 + 3352561 = 6910^2 + 1831^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51100661 is a prime.

It is a super-2 number, since 2×51100661² = 5222555109273842, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51100601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25550330 + 25550331.

It is an arithmetic number, because the mean of its divisors is an integer number (25550331).

Almost surely, 2^51100661 is an apocalyptic number.

It is an amenable number.

51100661 is a deficient number, since it is larger than the sum of its proper divisors (1).

51100661 is an equidigital number, since it uses as much as digits as its factorization.

51100661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 51100661 is about 7148.4726340667. The cubic root of 51100661 is about 371.0867997515.

Adding to 51100661 its reverse (16600115), we get a palindrome (67700776).

The spelling of 51100661 in words is "fifty-one million, one hundred thousand, six hundred sixty-one".