4001621 has 4 divisors (see below), whose sum is σ = 4309452. Its totient is φ = 3693792.

The previous prime is 4001617. The next prime is 4001629. The reversal of 4001621 is 1261004.

4001621 = 1414² + 1415².

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 1999396 + 2002225 = 1414^2 + 1415^2 .

It is a cyclic number.

It is not a de Polignac number, because 4001621 - 2² = 4001617 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 4001596 and 4001605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4001629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 153896 + ... + 153921.

It is an arithmetic number, because the mean of its divisors is an integer number (1077363).

Almost surely, 2^4001621 is an apocalyptic number.

4001621 is the 1415-th centered square number.

It is an amenable number.

4001621 is a deficient number, since it is larger than the sum of its proper divisors (307831).

4001621 is a wasteful number, since it uses less digits than its factorization.

4001621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307830.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 4001621 is about 2000.4052089514. The cubic root of 4001621 is about 158.7615454434.

Adding to 4001621 its reverse (1261004), we get a palindrome (5262625).

The spelling of 4001621 in words is "four million, one thousand, six hundred twenty-one".