1901968639 has 4 divisors (see below), whose sum is σ = 1948358160. Its totient is φ = 1855579120.

The previous prime is 1901968591. The next prime is 1901968643. The reversal of 1901968639 is 9368691091.

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

It is a cyclic number.

It is not a de Polignac number, because 1901968639 - 2⁹ = 1901968127 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 (1901968139) 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, 23194699 + ... + 23194780.

It is an arithmetic number, because the mean of its divisors is an integer number (487089540).

Almost surely, 2^1901968639 is an apocalyptic number.

1901968639 is a deficient number, since it is larger than the sum of its proper divisors (46389521).

1901968639 is an equidigital number, since it uses as much as digits as its factorization.

1901968639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46389520.

The product of its (nonzero) digits is 629856, while the sum is 52.

The square root of 1901968639 is about 43611.5654270745. The cubic root of 1901968639 is about 1238.9899507649.

The spelling of 1901968639 in words is "one billion, nine hundred one million, nine hundred sixty-eight thousand, six hundred thirty-nine".