19649887 has 2 divisors, whose sum is σ = 19649888. Its totient is φ = 19649886.

The previous prime is 19649867. The next prime is 19649893. The reversal of 19649887 is 78894691.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (78894691) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19649887 - 2⁷ = 19649759 is a prime.

It is a super-2 number, since 2×19649887² = 772236118225538, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19649837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9824943 + 9824944.

It is an arithmetic number, because the mean of its divisors is an integer number (9824944).

Almost surely, 2^19649887 is an apocalyptic number.

19649887 is a deficient number, since it is larger than the sum of its proper divisors (1).

19649887 is an equidigital number, since it uses as much as digits as its factorization.

19649887 is an evil number, because the sum of its binary digits is even.

The product of its digits is 870912, while the sum is 52.

The square root of 19649887 is about 4432.8193060399. The cubic root of 19649887 is about 269.8485066932.

The spelling of 19649887 in words is "nineteen million, six hundred forty-nine thousand, eight hundred eighty-seven".