1939999391 has 4 divisors (see below), whose sum is σ = 2116362984. Its totient is φ = 1763635800.

The previous prime is 1939999381. The next prime is 1939999487.

1939999391 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1939999391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1939999301) 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, 88181780 + ... + 88181801.

It is an arithmetic number, because the mean of its divisors is an integer number (529090746).

Almost surely, 2^1939999391 is an apocalyptic number.

1939999391 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1939999391 is a deficient number, since it is larger than the sum of its proper divisors (176363593).

1939999391 is a wasteful number, since it uses less digits than its factorization.

1939999391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176363592.

The product of its digits is 4782969, while the sum is 62.

The square root of 1939999391 is about 44045.4241777736. The cubic root of 1939999391 is about 1247.1935739738.

The spelling of 1939999391 in words is "one billion, nine hundred thirty-nine million, nine hundred ninety-nine thousand, three hundred ninety-one".