19872491 has 2 divisors, whose sum is σ = 19872492. Its totient is φ = 19872490.

The previous prime is 19872481. The next prime is 19872497. The reversal of 19872491 is 19427891.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19872491 - 2⁶ = 19872427 is a prime.

It is not a weakly prime, because it can be changed into another prime (19872497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9936245 + 9936246.

It is an arithmetic number, because the mean of its divisors is an integer number (9936246).

Almost surely, 2^19872491 is an apocalyptic number.

19872491 is a deficient number, since it is larger than the sum of its proper divisors (1).

19872491 is an equidigital number, since it uses as much as digits as its factorization.

19872491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 41.

The square root of 19872491 is about 4457.8572206835. The cubic root of 19872491 is about 270.8636769369.

The spelling of 19872491 in words is "nineteen million, eight hundred seventy-two thousand, four hundred ninety-one".