4006421 has 4 divisors (see below), whose sum is σ = 4091712. Its totient is φ = 3921132.

The previous prime is 4006417. The next prime is 4006423. The reversal of 4006421 is 1246004.

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 4006421 - 2² = 4006417 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 4006421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4006423) 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, 42575 + ... + 42668.

It is an arithmetic number, because the mean of its divisors is an integer number (1022928).

Almost surely, 2^4006421 is an apocalyptic number.

It is an amenable number.

4006421 is a deficient number, since it is larger than the sum of its proper divisors (85291).

4006421 is an equidigital number, since it uses as much as digits as its factorization.

4006421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85290.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 4006421 is about 2001.6046063096. The cubic root of 4006421 is about 158.8249989724.

The spelling of 4006421 in words is "four million, six thousand, four hundred twenty-one".