1838107921 has 4 divisors (see below), whose sum is σ = 1979500852. Its totient is φ = 1696714992.

The previous prime is 1838107919. The next prime is 1838107961. The reversal of 1838107921 is 1297018381.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1297018381 = 7457 ⋅173933.

It can be written as a sum of positive squares in 2 ways, for example, as 1002608896 + 835499025 = 31664^2 + 28905^2 .

It is a cyclic number.

It is not a de Polignac number, because 1838107921 - 2¹ = 1838107919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1838107961) 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, 70696446 + ... + 70696471.

It is an arithmetic number, because the mean of its divisors is an integer number (494875213).

Almost surely, 2^1838107921 is an apocalyptic number.

It is an amenable number.

1838107921 is a deficient number, since it is larger than the sum of its proper divisors (141392931).

1838107921 is a wasteful number, since it uses less digits than its factorization.

1838107921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141392930.

The product of its (nonzero) digits is 24192, while the sum is 40.

The square root of 1838107921 is about 42873.1608468515. The cubic root of 1838107921 is about 1224.9649682610.

The spelling of 1838107921 in words is "one billion, eight hundred thirty-eight million, one hundred seven thousand, nine hundred twenty-one".