420505621 has 4 divisors (see below), whose sum is σ = 420548544. Its totient is φ = 420462700.

The previous prime is 420505609. The next prime is 420505627. The reversal of 420505621 is 126505024.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 420505621 - 2⁷ = 420505493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (420505627) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1236 + ... + 29026.

It is an arithmetic number, because the mean of its divisors is an integer number (105137136).

Almost surely, 2^420505621 is an apocalyptic number.

It is an amenable number.

420505621 is a deficient number, since it is larger than the sum of its proper divisors (42923).

420505621 is a wasteful number, since it uses less digits than its factorization.

420505621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42922.

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 420505621 is about 20506.2337107524. The cubic root of 420505621 is about 749.1876365533.

The spelling of 420505621 in words is "four hundred twenty million, five hundred five thousand, six hundred twenty-one".