19897957 has 2 divisors, whose sum is σ = 19897958. Its totient is φ = 19897956.

The previous prime is 19897951. The next prime is 19897961. The reversal of 19897957 is 75979891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19633761 + 264196 = 4431^2 + 514^2 .

It is a cyclic number.

It is not a de Polignac number, because 19897957 - 2²³ = 11509349 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19897898 and 19897907.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19897951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9948978 + 9948979.

It is an arithmetic number, because the mean of its divisors is an integer number (9948979).

Almost surely, 2^19897957 is an apocalyptic number.

It is an amenable number.

19897957 is a deficient number, since it is larger than the sum of its proper divisors (1).

19897957 is an equidigital number, since it uses as much as digits as its factorization.

19897957 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1428840, while the sum is 55.

The square root of 19897957 is about 4460.7126112315. The cubic root of 19897957 is about 270.9793287701.

The spelling of 19897957 in words is "nineteen million, eight hundred ninety-seven thousand, nine hundred fifty-seven".