4001021 has 4 divisors (see below), whose sum is σ = 4094112. Its totient is φ = 3907932.

The previous prime is 4001017. The next prime is 4001027. The reversal of 4001021 is 1201004.

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 4001021 - 2² = 4001017 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 (4001027) 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, 46481 + ... + 46566.

It is an arithmetic number, because the mean of its divisors is an integer number (1023528).

Almost surely, 2^4001021 is an apocalyptic number.

It is an amenable number.

4001021 is a deficient number, since it is larger than the sum of its proper divisors (93091).

4001021 is an equidigital number, since it uses as much as digits as its factorization.

4001021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93090.

The product of its (nonzero) digits is 8, while the sum is 8.

The square root of 4001021 is about 2000.2552337139. The cubic root of 4001021 is about 158.7536101851.

Adding to 4001021 its reverse (1201004), we get a palindrome (5202025).

The spelling of 4001021 in words is "four million, one thousand, twenty-one".