15477994121 has 2 divisors, whose sum is σ = 15477994122. Its totient is φ = 15477994120.

The previous prime is 15477994067. The next prime is 15477994153. The reversal of 15477994121 is 12149977451.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15391131721 + 86862400 = 124061^2 + 9320^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15477994121 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 15477994121.

It is not a weakly prime, because it can be changed into another prime (15477994171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7738997060 + 7738997061.

It is an arithmetic number, because the mean of its divisors is an integer number (7738997061).

Almost surely, 2^15477994121 is an apocalyptic number.

It is an amenable number.

15477994121 is a deficient number, since it is larger than the sum of its proper divisors (1).

15477994121 is an equidigital number, since it uses as much as digits as its factorization.

15477994121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 635040, while the sum is 50.

The spelling of 15477994121 in words is "fifteen billion, four hundred seventy-seven million, nine hundred ninety-four thousand, one hundred twenty-one".