1939098721 has 4 divisors (see below), whose sum is σ = 2216112832. Its totient is φ = 1662084612.

The previous prime is 1939098719. The next prime is 1939098769. The reversal of 1939098721 is 1278909391.

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 1939098721 - 2¹ = 1939098719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1939090721) 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, 138507045 + ... + 138507058.

It is an arithmetic number, because the mean of its divisors is an integer number (554028208).

Almost surely, 2^1939098721 is an apocalyptic number.

It is an amenable number.

1939098721 is a deficient number, since it is larger than the sum of its proper divisors (277014111).

1939098721 is an equidigital number, since it uses as much as digits as its factorization.

1939098721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277014110.

The product of its (nonzero) digits is 244944, while the sum is 49.

The square root of 1939098721 is about 44035.1986597086. The cubic root of 1939098721 is about 1247.0005354736. Note that the first 3 decimals are identical.

The spelling of 1939098721 in words is "one billion, nine hundred thirty-nine million, ninety-eight thousand, seven hundred twenty-one".