51397639 has 2 divisors, whose sum is σ = 51397640. Its totient is φ = 51397638.

The previous prime is 51397631. The next prime is 51397669. The reversal of 51397639 is 93679315.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51397639 - 2³ = 51397631 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 51397595 and 51397604.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51397631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25698819 + 25698820.

It is an arithmetic number, because the mean of its divisors is an integer number (25698820).

Almost surely, 2^51397639 is an apocalyptic number.

51397639 is a deficient number, since it is larger than the sum of its proper divisors (1).

51397639 is an equidigital number, since it uses as much as digits as its factorization.

51397639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 153090, while the sum is 43.

The square root of 51397639 is about 7169.2146710780. The cubic root of 51397639 is about 371.8042843574.

The spelling of 51397639 in words is "fifty-one million, three hundred ninety-seven thousand, six hundred thirty-nine".