19651397 has 2 divisors, whose sum is σ = 19651398. Its totient is φ = 19651396.

The previous prime is 19651369. The next prime is 19651399. The reversal of 19651397 is 79315691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14638276 + 5013121 = 3826^2 + 2239^2 .

It is a cyclic number.

It is not a de Polignac number, because 19651397 - 2⁸ = 19651141 is a prime.

Together with 19651399, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19651399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9825698 + 9825699.

It is an arithmetic number, because the mean of its divisors is an integer number (9825699).

Almost surely, 2^19651397 is an apocalyptic number.

It is an amenable number.

19651397 is a deficient number, since it is larger than the sum of its proper divisors (1).

19651397 is an equidigital number, since it uses as much as digits as its factorization.

19651397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51030, while the sum is 41.

The square root of 19651397 is about 4432.9896232678. The cubic root of 19651397 is about 269.8554187059.

The spelling of 19651397 in words is "nineteen million, six hundred fifty-one thousand, three hundred ninety-seven".