4001320021 has 2 divisors, whose sum is σ = 4001320022. Its totient is φ = 4001320020.

The previous prime is 4001320003. The next prime is 4001320027. The reversal of 4001320021 is 1200231004.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3892012996 + 109307025 = 62386^2 + 10455^2 .

It is a cyclic number.

It is not a de Polignac number, because 4001320021 - 2⁵ = 4001319989 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 4001319983 and 4001320010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4001320027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2000660010 + 2000660011.

It is an arithmetic number, because the mean of its divisors is an integer number (2000660011).

Almost surely, 2^4001320021 is an apocalyptic number.

It is an amenable number.

4001320021 is a deficient number, since it is larger than the sum of its proper divisors (1).

4001320021 is an equidigital number, since it uses as much as digits as its factorization.

4001320021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 4001320021 is about 63255.9880248503. The cubic root of 4001320021 is about 1587.5756496572.

Adding to 4001320021 its reverse (1200231004), we get a palindrome (5201551025).

The spelling of 4001320021 in words is "four billion, one million, three hundred twenty thousand, twenty-one".