421572661 has 2 divisors, whose sum is σ = 421572662. Its totient is φ = 421572660.

The previous prime is 421572659. The next prime is 421572667. The reversal of 421572661 is 166275124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 241180900 + 180391761 = 15530^2 + 13431^2 .

It is a cyclic number.

It is not a de Polignac number, because 421572661 - 2¹ = 421572659 is a prime.

Together with 421572659, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (421572667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210786330 + 210786331.

It is an arithmetic number, because the mean of its divisors is an integer number (210786331).

Almost surely, 2^421572661 is an apocalyptic number.

It is an amenable number.

421572661 is a deficient number, since it is larger than the sum of its proper divisors (1).

421572661 is an equidigital number, since it uses as much as digits as its factorization.

421572661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20160, while the sum is 34.

The square root of 421572661 is about 20532.2346811057. The cubic root of 421572661 is about 749.8207933315.

The spelling of 421572661 in words is "four hundred twenty-one million, five hundred seventy-two thousand, six hundred sixty-one".