19990457 has 2 divisors, whose sum is σ = 19990458. Its totient is φ = 19990456.

The previous prime is 19990447. The next prime is 19990459. The reversal of 19990457 is 75409991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19971961 + 18496 = 4469^2 + 136^2 .

It is an emirp because it is prime and its reverse (75409991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19990457 - 2¹⁶ = 19924921 is a prime.

Together with 19990459, 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 (19990459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9995228 + 9995229.

It is an arithmetic number, because the mean of its divisors is an integer number (9995229).

Almost surely, 2^19990457 is an apocalyptic number.

It is an amenable number.

19990457 is a deficient number, since it is larger than the sum of its proper divisors (1).

19990457 is an equidigital number, since it uses as much as digits as its factorization.

19990457 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 102060, while the sum is 44.

The square root of 19990457 is about 4471.0688878612. The cubic root of 19990457 is about 271.3985819788.

The spelling of 19990457 in words is "nineteen million, nine hundred ninety thousand, four hundred fifty-seven".