51531620989 has 2 divisors, whose sum is σ = 51531620990. Its totient is φ = 51531620988.

The previous prime is 51531620977. The next prime is 51531621019. The reversal of 51531620989 is 98902613515.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50381393764 + 1150227225 = 224458^2 + 33915^2 .

It is a cyclic number.

It is not a de Polignac number, because 51531620989 - 2¹⁵ = 51531588221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51531620909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25765810494 + 25765810495.

It is an arithmetic number, because the mean of its divisors is an integer number (25765810495).

Almost surely, 2^51531620989 is an apocalyptic number.

It is an amenable number.

51531620989 is a deficient number, since it is larger than the sum of its proper divisors (1).

51531620989 is an equidigital number, since it uses as much as digits as its factorization.

51531620989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 583200, while the sum is 49.

The spelling of 51531620989 in words is "fifty-one billion, five hundred thirty-one million, six hundred twenty thousand, nine hundred eighty-nine".