19540621643 has 8 divisors (see below), whose sum is σ = 19874075760. Its totient is φ = 19207242880.

The previous prime is 19540621603. The next prime is 19540621651. The reversal of 19540621643 is 34612604591.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19540621643 - 2³⁰ = 18466879819 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19540621643.

It is not an unprimeable number, because it can be changed into a prime (19540621603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 817583 + ... + 841143.

It is an arithmetic number, because the mean of its divisors is an integer number (2484259470).

Almost surely, 2^19540621643 is an apocalyptic number.

19540621643 is a deficient number, since it is larger than the sum of its proper divisors (333454117).

19540621643 is a wasteful number, since it uses less digits than its factorization.

19540621643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37677.

The product of its (nonzero) digits is 155520, while the sum is 41.

The spelling of 19540621643 in words is "nineteen billion, five hundred forty million, six hundred twenty-one thousand, six hundred forty-three".