1981419401641 has 3 divisors (see below), whose sum is σ = 1981420809271. Its totient is φ = 1981417994012.

The previous prime is 1981419401627. The next prime is 1981419401669. The reversal of 1981419401641 is 1461049141891.

The square root of 1981419401641 is 1407629.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 816530911641 + 1164888490000 = 903621^2 + 1079300^2 .

It is not a de Polignac number, because 1981419401641 - 2⁵ = 1981419401609 is a prime.

It is a super-3 number, since 3×1981419401641³ (a number of 38 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1981419471641) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 703815 + ... + 2111443.

Almost surely, 2^{1981419401641} is an apocalyptic number.

1981419401641 is the 1407629-th square number.

1981419401641 is the 703815-th centered octagonal number.

It is an amenable number.

1981419401641 is a deficient number, since it is larger than the sum of its proper divisors (1407630).

1981419401641 is an frugal number, since it uses more digits than its factorization.

1981419401641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2815258 (or 1407629 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 49.

Multiplying 1981419401641 by its sum of digits (49), we get a square (97089550680409 = 9853403²).

The spelling of 1981419401641 in words is "one trillion, nine hundred eighty-one billion, four hundred nineteen million, four hundred one thousand, six hundred forty-one".