4002421 has 4 divisors (see below), whose sum is σ = 4013100. Its totient is φ = 3991744.

The previous prime is 4002403. The next prime is 4002431. The reversal of 4002421 is 1242004.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2340900 + 1661521 = 1530^2 + 1289^2 .

It is a cyclic number.

It is not a de Polignac number, because 4002421 - 2⁵ = 4002389 is a prime.

It is a super-2 number, since 2×4002421² = 32038747722482, which contains 22 as substring.

It is a Duffinian number.

4002421 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4002431) 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, 4756 + ... + 5533.

It is an arithmetic number, because the mean of its divisors is an integer number (1003275).

Almost surely, 2^4002421 is an apocalyptic number.

It is an amenable number.

4002421 is a deficient number, since it is larger than the sum of its proper divisors (10679).

4002421 is a wasteful number, since it uses less digits than its factorization.

4002421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10678.

The product of its (nonzero) digits is 64, while the sum is 13.

The square root of 4002421 is about 2000.6051584458. The cubic root of 4002421 is about 158.7721245540.

Adding to 4002421 its reverse (1242004), we get a palindrome (5244425).

The spelling of 4002421 in words is "four million, two thousand, four hundred twenty-one".