400620221 has 2 divisors, whose sum is σ = 400620222. Its totient is φ = 400620220.

The previous prime is 400620203. The next prime is 400620229. The reversal of 400620221 is 122026004.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 400560196 + 60025 = 20014^2 + 245^2 .

It is a cyclic number.

It is not a de Polignac number, because 400620221 - 2²² = 396425917 is a prime.

It is a super-2 number, since 2×400620221² = 320993122948177682, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 400620221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400620229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200310110 + 200310111.

It is an arithmetic number, because the mean of its divisors is an integer number (200310111).

Almost surely, 2^400620221 is an apocalyptic number.

It is an amenable number.

400620221 is a deficient number, since it is larger than the sum of its proper divisors (1).

400620221 is an equidigital number, since it uses as much as digits as its factorization.

400620221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 400620221 is about 20015.4995191227. The cubic root of 400620221 is about 737.1869220209.

Adding to 400620221 its reverse (122026004), we get a palindrome (522646225).

The spelling of 400620221 in words is "four hundred million, six hundred twenty thousand, two hundred twenty-one".