1838897721 has 20 divisors (see below), whose sum is σ = 2758422964. Its totient is φ = 1220832000.

The previous prime is 1838897693. The next prime is 1838897737. The reversal of 1838897721 is 1277988381.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 1480325625 + 358572096 = 38475^2 + 18936^2 .

It is not a de Polignac number, because 1838897721 - 2¹¹ = 1838895673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1838897761) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 27580 + ... + 66621.

Almost surely, 2^1838897721 is an apocalyptic number.

It is an amenable number.

1838897721 is a deficient number, since it is larger than the sum of its proper divisors (919525243).

1838897721 is an equidigital number, since it uses as much as digits as its factorization.

1838897721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94454 (or 94445 counting only the distinct ones).

The product of its digits is 1354752, while the sum is 54.

The square root of 1838897721 is about 42882.3707483623. The cubic root of 1838897721 is about 1225.1403911846.

The spelling of 1838897721 in words is "one billion, eight hundred thirty-eight million, eight hundred ninety-seven thousand, seven hundred twenty-one".