51451021 has 2 divisors, whose sum is σ = 51451022. Its totient is φ = 51451020.

The previous prime is 51451003. The next prime is 51451039. The reversal of 51451021 is 12015415.

It is a balanced prime because it is at equal distance from previous prime (51451003) and next prime (51451039).

It can be written as a sum of positive squares in only one way, i.e., 39816100 + 11634921 = 6310^2 + 3411^2 .

It is a cyclic number.

It is not a de Polignac number, because 51451021 - 2¹³ = 51442829 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51451021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51451721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25725510 + 25725511.

It is an arithmetic number, because the mean of its divisors is an integer number (25725511).

Almost surely, 2^51451021 is an apocalyptic number.

It is an amenable number.

51451021 is a deficient number, since it is larger than the sum of its proper divisors (1).

51451021 is an equidigital number, since it uses as much as digits as its factorization.

51451021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 200, while the sum is 19.

The square root of 51451021 is about 7172.9367068168. The cubic root of 51451021 is about 371.9329594570.

Adding to 51451021 its reverse (12015415), we get a palindrome (63466436).

The spelling of 51451021 in words is "fifty-one million, four hundred fifty-one thousand, twenty-one".