4021197991 has 4 divisors (see below), whose sum is σ = 4022719792. Its totient is φ = 4019676192.

The previous prime is 4021197989. The next prime is 4021198007. The reversal of 4021197991 is 1997911204.

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 4021197991 - 2¹ = 4021197989 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 (4021197931) 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, 756930 + ... + 762223.

It is an arithmetic number, because the mean of its divisors is an integer number (1005679948).

Almost surely, 2^4021197991 is an apocalyptic number.

4021197991 is a deficient number, since it is larger than the sum of its proper divisors (1521801).

4021197991 is a wasteful number, since it uses less digits than its factorization.

4021197991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1521800.

The product of its (nonzero) digits is 40824, while the sum is 43.

The square root of 4021197991 is about 63412.9165943343. The cubic root of 4021197991 is about 1590.2002557525.

The spelling of 4021197991 in words is "four billion, twenty-one million, one hundred ninety-seven thousand, nine hundred ninety-one".