19881929 has 2 divisors, whose sum is σ = 19881930. Its totient is φ = 19881928.

The previous prime is 19881889. The next prime is 19881941. The reversal of 19881929 is 92918891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19758025 + 123904 = 4445^2 + 352^2 .

It is a cyclic number.

It is not a de Polignac number, because 19881929 - 2¹⁶ = 19816393 is a prime.

It is a super-2 number, since 2×19881929² = 790582201522082, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19881229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9940964 + 9940965.

It is an arithmetic number, because the mean of its divisors is an integer number (9940965).

Almost surely, 2^19881929 is an apocalyptic number.

It is an amenable number.

19881929 is a deficient number, since it is larger than the sum of its proper divisors (1).

19881929 is an equidigital number, since it uses as much as digits as its factorization.

19881929 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 47.

The square root of 19881929 is about 4458.9156753632. The cubic root of 19881929 is about 270.9065503875.

The spelling of 19881929 in words is "nineteen million, eight hundred eighty-one thousand, nine hundred twenty-nine".