1821745791 has 12 divisors (see below), whose sum is σ = 2635796800. Its totient is φ = 1212472800.

The previous prime is 1821745763. The next prime is 1821745811. The reversal of 1821745791 is 1975471281.

It is a happy number.

1821745791 is a `hidden beast` number, since 1 + 8 + 2 + 1 + 74 + 579 + 1 = 666.

It is not a de Polignac number, because 1821745791 - 2⁵ = 1821745759 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821745591) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 162991 + ... + 173808.

Almost surely, 2^1821745791 is an apocalyptic number.

1821745791 is a deficient number, since it is larger than the sum of its proper divisors (814051009).

1821745791 is a wasteful number, since it uses less digits than its factorization.

1821745791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 337406 (or 337403 counting only the distinct ones).

The product of its digits is 141120, while the sum is 45.

The square root of 1821745791 is about 42681.9140971911. The cubic root of 1821745791 is about 1221.3194072483.

The spelling of 1821745791 in words is "one billion, eight hundred twenty-one million, seven hundred forty-five thousand, seven hundred ninety-one".