51172621 has 2 divisors, whose sum is σ = 51172622. Its totient is φ = 51172620.

The previous prime is 51172619. The next prime is 51172663. The reversal of 51172621 is 12627115.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 29214025 + 21958596 = 5405^2 + 4686^2 .

It is a cyclic number.

It is not a de Polignac number, because 51172621 - 2¹ = 51172619 is a prime.

Together with 51172619, 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 (51172691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25586310 + 25586311.

It is an arithmetic number, because the mean of its divisors is an integer number (25586311).

Almost surely, 2^51172621 is an apocalyptic number.

It is an amenable number.

51172621 is a deficient number, since it is larger than the sum of its proper divisors (1).

51172621 is an equidigital number, since it uses as much as digits as its factorization.

51172621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 840, while the sum is 25.

The square root of 51172621 is about 7153.5041063803. The cubic root of 51172621 is about 371.2609063142.

Adding to 51172621 its reverse (12627115), we get a palindrome (63799736).

The spelling of 51172621 in words is "fifty-one million, one hundred seventy-two thousand, six hundred twenty-one".