19997556546 has 64 divisors (see below), whose sum is σ = 44335890432. Its totient is φ = 5962320000.

The previous prime is 19997556529. The next prime is 19997556577. The reversal of 19997556546 is 64565579991.

It is a super-3 number, since 3×19997556546³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2437311 + ... + 2445501.

It is an arithmetic number, because the mean of its divisors is an integer number (692748288).

Almost surely, 2^19997556546 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19997556546, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22167945216).

19997556546 is an abundant number, since it is smaller than the sum of its proper divisors (24338333886).

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

19997556546 is a wasteful number, since it uses less digits than its factorization.

19997556546 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8799.

The product of its digits is 91854000, while the sum is 66.

The spelling of 19997556546 in words is "nineteen billion, nine hundred ninety-seven million, five hundred fifty-six thousand, five hundred forty-six".