15820397 has 2 divisors, whose sum is σ = 15820398. Its totient is φ = 15820396.

The previous prime is 15820393. The next prime is 15820417. The reversal of 15820397 is 79302851.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7946761 + 7873636 = 2819^2 + 2806^2 .

It is an emirp because it is prime and its reverse (79302851) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15820397 - 2² = 15820393 is a prime.

It is a super-2 number, since 2×15820397² = 500569922475218, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15820391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7910198 + 7910199.

It is an arithmetic number, because the mean of its divisors is an integer number (7910199).

Almost surely, 2^15820397 is an apocalyptic number.

It is an amenable number.

15820397 is a deficient number, since it is larger than the sum of its proper divisors (1).

15820397 is an equidigital number, since it uses as much as digits as its factorization.

15820397 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 15820397 is about 3977.4862664753. The cubic root of 15820397 is about 251.0378032298.

The spelling of 15820397 in words is "fifteen million, eight hundred twenty thousand, three hundred ninety-seven".