19812642705 has 24 divisors (see below), whose sum is σ = 34407870120. Its totient is φ = 10546448640.

The previous prime is 19812642671. The next prime is 19812642709. The reversal of 19812642705 is 50724621891.

It can be written as a sum of positive squares in 4 ways, for example, as 778577409 + 19034065296 = 27903^2 + 137964^2 .

It is not a de Polignac number, because 19812642705 - 2⁸ = 19812642449 is a prime.

It is a super-3 number, since 3×19812642705³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (19812642709) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 399090 + ... + 445979.

It is an arithmetic number, because the mean of its divisors is an integer number (1433661255).

Almost surely, 2^19812642705 is an apocalyptic number.

19812642705 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19812642705 is a deficient number, since it is larger than the sum of its proper divisors (14595227415).

19812642705 is a wasteful number, since it uses less digits than its factorization.

19812642705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 845601 (or 845598 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The spelling of 19812642705 in words is "nineteen billion, eight hundred twelve million, six hundred forty-two thousand, seven hundred five".