1841397721 has 8 divisors (see below), whose sum is σ = 1950578280. Its totient is φ = 1732313088.

The previous prime is 1841397703. The next prime is 1841397731. The reversal of 1841397721 is 1277931481.

It can be written as a sum of positive squares in 4 ways, for example, as 879715600 + 961682121 = 29660^2 + 31011^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1841397721 - 2⁵ = 1841397689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1841397731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17625 + ... + 63193.

It is an arithmetic number, because the mean of its divisors is an integer number (243822285).

Almost surely, 2^1841397721 is an apocalyptic number.

It is an amenable number.

1841397721 is a deficient number, since it is larger than the sum of its proper divisors (109180559).

1841397721 is a wasteful number, since it uses less digits than its factorization.

1841397721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47963.

The product of its digits is 84672, while the sum is 43.

The square root of 1841397721 is about 42911.5103556144. The cubic root of 1841397721 is about 1225.6953366823.

The spelling of 1841397721 in words is "one billion, eight hundred forty-one million, three hundred ninety-seven thousand, seven hundred twenty-one".