19881541 has 2 divisors, whose sum is σ = 19881542. Its totient is φ = 19881540.

The previous prime is 19881503. The next prime is 19881557. The reversal of 19881541 is 14518891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16892100 + 2989441 = 4110^2 + 1729^2 .

It is an emirp because it is prime and its reverse (14518891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19881541 - 2¹⁷ = 19750469 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19881541.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19881241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9940770 + 9940771.

It is an arithmetic number, because the mean of its divisors is an integer number (9940771).

Almost surely, 2^19881541 is an apocalyptic number.

It is an amenable number.

19881541 is a deficient number, since it is larger than the sum of its proper divisors (1).

19881541 is an equidigital number, since it uses as much as digits as its factorization.

19881541 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11520, while the sum is 37.

The square root of 19881541 is about 4458.8721668153. The cubic root of 19881541 is about 270.9047881101.

The spelling of 19881541 in words is "nineteen million, eight hundred eighty-one thousand, five hundred forty-one".