15221451397 has 2 divisors, whose sum is σ = 15221451398. Its totient is φ = 15221451396.

The previous prime is 15221451379. The next prime is 15221451403. The reversal of 15221451397 is 79315412251.

Together with previous prime (15221451379) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13153566721 + 2067884676 = 114689^2 + 45474^2 .

It is a cyclic number.

It is not a de Polignac number, because 15221451397 - 2¹⁹ = 15220927109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15221451337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7610725698 + 7610725699.

It is an arithmetic number, because the mean of its divisors is an integer number (7610725699).

Almost surely, 2^15221451397 is an apocalyptic number.

It is an amenable number.

15221451397 is a deficient number, since it is larger than the sum of its proper divisors (1).

15221451397 is an equidigital number, since it uses as much as digits as its factorization.

15221451397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 75600, while the sum is 40.

The spelling of 15221451397 in words is "fifteen billion, two hundred twenty-one million, four hundred fifty-one thousand, three hundred ninety-seven".