19897457 has 4 divisors (see below), whose sum is σ = 19910256. Its totient is φ = 19884660.

The previous prime is 19897387. The next prime is 19897481. The reversal of 19897457 is 75479891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 75479891 = 1223 ⋅61717.

It is a cyclic number.

It is not a de Polignac number, because 19897457 - 2¹⁰ = 19896433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19897487) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3683 + ... + 7304.

It is an arithmetic number, because the mean of its divisors is an integer number (4977564).

Almost surely, 2^19897457 is an apocalyptic number.

It is an amenable number.

19897457 is a deficient number, since it is larger than the sum of its proper divisors (12799).

19897457 is a wasteful number, since it uses less digits than its factorization.

19897457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12798.

The product of its digits is 635040, while the sum is 50.

The square root of 19897457 is about 4460.6565660225. The cubic root of 19897457 is about 270.9770590095.

The spelling of 19897457 in words is "nineteen million, eight hundred ninety-seven thousand, four hundred fifty-seven".