4000421391 has 4 divisors (see below), whose sum is σ = 5333895192. Its totient is φ = 2666947592.

The previous prime is 4000421363. The next prime is 4000421393. The reversal of 4000421391 is 1931240004.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4000421391 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4000421393) 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, 666736896 + ... + 666736901.

It is an arithmetic number, because the mean of its divisors is an integer number (1333473798).

Almost surely, 2^4000421391 is an apocalyptic number.

4000421391 is a deficient number, since it is larger than the sum of its proper divisors (1333473801).

4000421391 is a wasteful number, since it uses less digits than its factorization.

4000421391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1333473800.

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 4000421391 is about 63248.8845039974. The cubic root of 4000421391 is about 1587.4567930539.

Adding to 4000421391 its reverse (1931240004), we get a palindrome (5931661395).

The spelling of 4000421391 in words is "four billion, four hundred twenty-one thousand, three hundred ninety-one".