1968894021 has 4 divisors (see below), whose sum is σ = 2625192032. Its totient is φ = 1312596012.

The previous prime is 1968893977. The next prime is 1968894029. The reversal of 1968894021 is 1204988691.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1204988691 = 3 ⋅401662897.

It is not a de Polignac number, because 1968894021 - 2⁶ = 1968893957 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 (1968894029) 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, 328149001 + ... + 328149006.

It is an arithmetic number, because the mean of its divisors is an integer number (656298008).

Almost surely, 2^1968894021 is an apocalyptic number.

It is an amenable number.

1968894021 is a deficient number, since it is larger than the sum of its proper divisors (656298011).

1968894021 is an equidigital number, since it uses as much as digits as its factorization.

1968894021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 656298010.

The product of its (nonzero) digits is 248832, while the sum is 48.

The square root of 1968894021 is about 44372.2212763797. The cubic root of 1968894021 is about 1253.3550446968.

The spelling of 1968894021 in words is "one billion, nine hundred sixty-eight million, eight hundred ninety-four thousand, twenty-one".