19540621644 has 24 divisors (see below), whose sum is σ = 48276830448. Its totient is φ = 6130391040.

The previous prime is 19540621603. The next prime is 19540621651. The reversal of 19540621644 is 44612604591.

It is a super-2 number, since 2×19540621644² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 19540621596 and 19540621605.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47893477 + ... + 47893884.

It is an arithmetic number, because the mean of its divisors is an integer number (2011534602).

Almost surely, 2^19540621644 is an apocalyptic number.

It is an amenable number.

19540621644 is an abundant number, since it is smaller than the sum of its proper divisors (28736208804).

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

19540621644 is a wasteful number, since it uses less digits than its factorization.

19540621644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95787385 (or 95787383 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 42.

The spelling of 19540621644 in words is "nineteen billion, five hundred forty million, six hundred twenty-one thousand, six hundred forty-four".