19901026988 has 6 divisors (see below), whose sum is σ = 34826797236. Its totient is φ = 9950513492.

The previous prime is 19901026973. The next prime is 19901027171. The reversal of 19901026988 is 88962010991.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2487628370 + ... + 2487628377.

It is an arithmetic number, because the mean of its divisors is an integer number (5804466206).

Almost surely, 2^19901026988 is an apocalyptic number.

It is an amenable number.

19901026988 is a deficient number, since it is larger than the sum of its proper divisors (14925770248).

19901026988 is a wasteful number, since it uses less digits than its factorization.

19901026988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4975256751 (or 4975256749 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 53.

Adding to 19901026988 its sum of digits (53), we get a square (19901027041 = 141071²).

The spelling of 19901026988 in words is "nineteen billion, nine hundred one million, twenty-six thousand, nine hundred eighty-eight".