19903861 has 2 divisors, whose sum is σ = 19903862. Its totient is φ = 19903860.

The previous prime is 19903853. The next prime is 19903903. The reversal of 19903861 is 16830991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11088900 + 8814961 = 3330^2 + 2969^2 .

It is a cyclic number.

It is not a de Polignac number, because 19903861 - 2³ = 19903853 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19903861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19903061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9951930 + 9951931.

It is an arithmetic number, because the mean of its divisors is an integer number (9951931).

Almost surely, 2^19903861 is an apocalyptic number.

It is an amenable number.

19903861 is a deficient number, since it is larger than the sum of its proper divisors (1).

19903861 is an equidigital number, since it uses as much as digits as its factorization.

19903861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 37.

The square root of 19903861 is about 4461.3743398195. The cubic root of 19903861 is about 271.0061272290.

The spelling of 19903861 in words is "nineteen million, nine hundred three thousand, eight hundred sixty-one".