19439901021 has 16 divisors (see below), whose sum is σ = 26263733760. Its totient is φ = 12789107760.

The previous prime is 19439900957. The next prime is 19439901029. The reversal of 19439901021 is 12010993491.

It is not a de Polignac number, because 19439901021 - 2⁶ = 19439900957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19439901029) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67825 + ... + 208518.

It is an arithmetic number, because the mean of its divisors is an integer number (1641483360).

Almost surely, 2^19439901021 is an apocalyptic number.

It is an amenable number.

19439901021 is a deficient number, since it is larger than the sum of its proper divisors (6823832739).

19439901021 is a wasteful number, since it uses less digits than its factorization.

19439901021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276656.

The product of its (nonzero) digits is 17496, while the sum is 39.

The spelling of 19439901021 in words is "nineteen billion, four hundred thirty-nine million, nine hundred one thousand, twenty-one".