12577778621 has 2 divisors, whose sum is σ = 12577778622. Its totient is φ = 12577778620.

The previous prime is 12577778537. The next prime is 12577778623. The reversal of 12577778621 is 12687777521.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7381387225 + 5196391396 = 85915^2 + 72086^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12577778621 is a prime.

Together with 12577778623, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12577778623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6288889310 + 6288889311.

It is an arithmetic number, because the mean of its divisors is an integer number (6288889311).

Almost surely, 2^12577778621 is an apocalyptic number.

It is an amenable number.

12577778621 is a deficient number, since it is larger than the sum of its proper divisors (1).

12577778621 is an equidigital number, since it uses as much as digits as its factorization.

12577778621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304960, while the sum is 53.

The spelling of 12577778621 in words is "twelve billion, five hundred seventy-seven million, seven hundred seventy-eight thousand, six hundred twenty-one".