15988121 has 2 divisors, whose sum is σ = 15988122. Its totient is φ = 15988120.

The previous prime is 15988117. The next prime is 15988123. The reversal of 15988121 is 12188951.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11806096 + 4182025 = 3436^2 + 2045^2 .

It is an emirp because it is prime and its reverse (12188951) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15988121 - 2² = 15988117 is a prime.

It is a super-2 number, since 2×15988121² = 511240026221282, which contains 22 as substring.

Together with 15988123, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (15988123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7994060 + 7994061.

It is an arithmetic number, because the mean of its divisors is an integer number (7994061).

Almost surely, 2^15988121 is an apocalyptic number.

It is an amenable number.

15988121 is a deficient number, since it is larger than the sum of its proper divisors (1).

15988121 is an equidigital number, since it uses as much as digits as its factorization.

15988121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5760, while the sum is 35.

The square root of 15988121 is about 3998.5148492909. The cubic root of 15988121 is about 251.9218336973.

The spelling of 15988121 in words is "fifteen million, nine hundred eighty-eight thousand, one hundred twenty-one".