19124951821 has 2 divisors, whose sum is σ = 19124951822. Its totient is φ = 19124951820.

The previous prime is 19124951801. The next prime is 19124951827. The reversal of 19124951821 is 12815942191.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15547596100 + 3577355721 = 124690^2 + 59811^2 .

It is a cyclic number.

It is not a de Polignac number, because 19124951821 - 2⁷ = 19124951693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19124951827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9562475910 + 9562475911.

It is an arithmetic number, because the mean of its divisors is an integer number (9562475911).

Almost surely, 2^19124951821 is an apocalyptic number.

It is an amenable number.

19124951821 is a deficient number, since it is larger than the sum of its proper divisors (1).

19124951821 is an equidigital number, since it uses as much as digits as its factorization.

19124951821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 43.

The spelling of 19124951821 in words is "nineteen billion, one hundred twenty-four million, nine hundred fifty-one thousand, eight hundred twenty-one".