51409621 has 2 divisors, whose sum is σ = 51409622. Its totient is φ = 51409620.

The previous prime is 51409601. The next prime is 51409627. The reversal of 51409621 is 12690415.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42107121 + 9302500 = 6489^2 + 3050^2 .

It is a cyclic number.

It is not a de Polignac number, because 51409621 - 2¹⁹ = 50885333 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51409621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51409627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25704810 + 25704811.

It is an arithmetic number, because the mean of its divisors is an integer number (25704811).

Almost surely, 2^51409621 is an apocalyptic number.

It is an amenable number.

51409621 is a deficient number, since it is larger than the sum of its proper divisors (1).

51409621 is an equidigital number, since it uses as much as digits as its factorization.

51409621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 51409621 is about 7170.0502787637. The cubic root of 51409621 is about 371.8331742240.

The spelling of 51409621 in words is "fifty-one million, four hundred nine thousand, six hundred twenty-one".