19923729408 has 528 divisors, whose sum is σ = 67596197760. Its totient is φ = 5806080000.

The previous prime is 19923729389. The next prime is 19923729409. The reversal of 19923729408 is 80492732991.

19923729408 is a `hidden beast` number, since 199 + 23 + 7 + 29 + 408 = 666.

It is a tau number, because it is divible by the number of its divisors (528).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19923729409) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 79377283 + ... + 79377533.

Almost surely, 2^19923729408 is an apocalyptic number.

19923729408 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19923729408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33798098880).

19923729408 is an abundant number, since it is smaller than the sum of its proper divisors (47672468352).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19923729408 is a wasteful number, since it uses less digits than its factorization.

19923729408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 326 (or 296 counting only the distinct ones).

The product of its (nonzero) digits is 1959552, while the sum is 54.

The spelling of 19923729408 in words is "nineteen billion, nine hundred twenty-three million, seven hundred twenty-nine thousand, four hundred eight".