3988991 has 2 divisors, whose sum is σ = 3988992. Its totient is φ = 3988990.

The previous prime is 3988969. The next prime is 3989003. The reversal of 3988991 is 1998893.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 3988991 - 2¹⁸ = 3726847 is a prime.

It is a plaindrome in base 16.

It is a nialpdrome in base 13.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3988961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1994495 + 1994496.

It is an arithmetic number, because the mean of its divisors is an integer number (1994496).

Almost surely, 2^3988991 is an apocalyptic number.

3988991 is a deficient number, since it is larger than the sum of its proper divisors (1).

3988991 is an equidigital number, since it uses as much as digits as its factorization.

3988991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 47.

The square root of 3988991 is about 1997.2458536695. The cubic root of 3988991 is about 158.5943405698.

The spelling of 3988991 in words is "three million, nine hundred eighty-eight thousand, nine hundred ninety-one".