51779621 has 2 divisors, whose sum is σ = 51779622. Its totient is φ = 51779620.

The previous prime is 51779599. The next prime is 51779653. The reversal of 51779621 is 12697715.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51696100 + 83521 = 7190^2 + 289^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51779621 is a prime.

It is a super-2 number, since 2×51779621² = 5362258301807282, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51779821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25889810 + 25889811.

It is an arithmetic number, because the mean of its divisors is an integer number (25889811).

Almost surely, 2^51779621 is an apocalyptic number.

It is an amenable number.

51779621 is a deficient number, since it is larger than the sum of its proper divisors (1).

51779621 is an equidigital number, since it uses as much as digits as its factorization.

51779621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26460, while the sum is 38.

The square root of 51779621 is about 7195.8057922654. The cubic root of 51779621 is about 372.7230824453.

The spelling of 51779621 in words is "fifty-one million, seven hundred seventy-nine thousand, six hundred twenty-one".