3976389899921 has 4 divisors (see below), whose sum is σ = 3993907036272. Its totient is φ = 3958872763572.

The previous prime is 3976389899891. The next prime is 3976389899939. The reversal of 3976389899921 is 1299989836793.

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 3976389899921 - 2¹⁸ = 3976389637777 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 3976389899921.

It is not an unprimeable number, because it can be changed into a prime (3976389899941) 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, 8758567835 + ... + 8758568288.

It is an arithmetic number, because the mean of its divisors is an integer number (998476759068).

Almost surely, 2^{3976389899921} is an apocalyptic number.

It is an amenable number.

3976389899921 is a deficient number, since it is larger than the sum of its proper divisors (17517136351).

3976389899921 is a wasteful number, since it uses less digits than its factorization.

3976389899921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17517136350.

The product of its digits is 2857026816, while the sum is 83.

The spelling of 3976389899921 in words is "three trillion, nine hundred seventy-six billion, three hundred eighty-nine million, eight hundred ninety-nine thousand, nine hundred twenty-one".