51205639 has 2 divisors, whose sum is σ = 51205640. Its totient is φ = 51205638.

The previous prime is 51205633. The next prime is 51205663. The reversal of 51205639 is 93650215.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51205639 - 2⁹ = 51205127 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51205639.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51205633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25602819 + 25602820.

It is an arithmetic number, because the mean of its divisors is an integer number (25602820).

Almost surely, 2^51205639 is an apocalyptic number.

51205639 is a deficient number, since it is larger than the sum of its proper divisors (1).

51205639 is an equidigital number, since it uses as much as digits as its factorization.

51205639 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8100, while the sum is 31.

The square root of 51205639 is about 7155.8115542543. The cubic root of 51205639 is about 371.3407384383.

The spelling of 51205639 in words is "fifty-one million, two hundred five thousand, six hundred thirty-nine".