1881783721 has 4 divisors (see below), whose sum is σ = 1881931392. Its totient is φ = 1881636052.

The previous prime is 1881783679. The next prime is 1881783727. The reversal of 1881783721 is 1273871881.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1881783721 - 2¹³ = 1881775529 is a prime.

It is a super-2 number, since 2×1881783721² = 7082219945241211682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1881783727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52705 + ... + 80878.

It is an arithmetic number, because the mean of its divisors is an integer number (470482848).

Almost surely, 2^1881783721 is an apocalyptic number.

It is an amenable number.

1881783721 is a deficient number, since it is larger than the sum of its proper divisors (147671).

1881783721 is a wasteful number, since it uses less digits than its factorization.

1881783721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147670.

The product of its digits is 150528, while the sum is 46.

The square root of 1881783721 is about 43379.5311293241. The cubic root of 1881783721 is about 1234.5913668264.

The spelling of 1881783721 in words is "one billion, eight hundred eighty-one million, seven hundred eighty-three thousand, seven hundred twenty-one".