397555819 has 2 divisors, whose sum is σ = 397555820. Its totient is φ = 397555818.

The previous prime is 397555817. The next prime is 397555831. The reversal of 397555819 is 918555793.

It is a weak prime.

It is an emirp because it is prime and its reverse (918555793) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 397555819 - 2¹ = 397555817 is a prime.

It is a super-2 number, since 2×397555819² = 316101258441521522, which contains 22 as substring.

Together with 397555817, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (397555813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 198777909 + 198777910.

It is an arithmetic number, because the mean of its divisors is an integer number (198777910).

Almost surely, 2^397555819 is an apocalyptic number.

397555819 is a deficient number, since it is larger than the sum of its proper divisors (1).

397555819 is an equidigital number, since it uses as much as digits as its factorization.

397555819 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1701000, while the sum is 52.

The square root of 397555819 is about 19938.8018446445. The cubic root of 397555819 is about 735.3024926101.

The spelling of 397555819 in words is "three hundred ninety-seven million, five hundred fifty-five thousand, eight hundred nineteen".