400220521 has 2 divisors, whose sum is σ = 400220522. Its totient is φ = 400220520.

The previous prime is 400220507. The next prime is 400220533. The reversal of 400220521 is 125022004.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 241460521 + 158760000 = 15539^2 + 12600^2 .

It is a cyclic number.

It is not a de Polignac number, because 400220521 - 2⁵ = 400220489 is a prime.

It is a super-2 number, since 2×400220521² = 320352930859022882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 400220495 and 400220504.

It is not a weakly prime, because it can be changed into another prime (400220591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200110260 + 200110261.

It is an arithmetic number, because the mean of its divisors is an integer number (200110261).

Almost surely, 2^400220521 is an apocalyptic number.

It is an amenable number.

400220521 is a deficient number, since it is larger than the sum of its proper divisors (1).

400220521 is an equidigital number, since it uses as much as digits as its factorization.

400220521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 400220521 is about 20005.5122653733. The cubic root of 400220521 is about 736.9416759051.

Adding to 400220521 its reverse (125022004), we get a palindrome (525242525).

The spelling of 400220521 in words is "four hundred million, two hundred twenty thousand, five hundred twenty-one".