19281821881 has 27 divisors (see below), whose sum is σ = 22798760421. Its totient is φ = 16259833464.

The previous prime is 19281821857. The next prime is 19281821891. The reversal of 19281821881 is 18812818291.

The square root of 19281821881 is 138859.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 19281821881 - 2⁹ = 19281821369 is a prime.

It is a super-2 number, since 2×19281821881² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19281821831) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 80676960 + ... + 80677198.

Almost surely, 2^19281821881 is an apocalyptic number.

19281821881 is the 138859-th square number.

19281821881 is the 69430-th centered octagonal number.

It is an amenable number.

19281821881 is a deficient number, since it is larger than the sum of its proper divisors (3516938540).

19281821881 is an frugal number, since it uses more digits than its factorization.

19281821881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 658 (or 329 counting only the distinct ones).

The product of its digits is 147456, while the sum is 49.

Multiplying 19281821881 by its sum of digits (49), we get a square (944809272169 = 972013²).

19281821881 divided by its sum of digits (49) gives a square (393506569 = 19837²).

The spelling of 19281821881 in words is "nineteen billion, two hundred eighty-one million, eight hundred twenty-one thousand, eight hundred eighty-one".