421520217 has 4 divisors (see below), whose sum is σ = 562026960. Its totient is φ = 281013476.

The previous prime is 421520207. The next prime is 421520233. The reversal of 421520217 is 712025124.

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.

It is a cyclic number.

It is not a de Polignac number, because 421520217 - 2⁶ = 421520153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (421520207) 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 in 3 ways as a sum of consecutive naturals, for example, 70253367 + ... + 70253372.

It is an arithmetic number, because the mean of its divisors is an integer number (140506740).

Almost surely, 2^421520217 is an apocalyptic number.

It is an amenable number.

421520217 is a deficient number, since it is larger than the sum of its proper divisors (140506743).

421520217 is a wasteful number, since it uses less digits than its factorization.

421520217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140506742.

The product of its (nonzero) digits is 1120, while the sum is 24.

The square root of 421520217 is about 20530.9575275972. The cubic root of 421520217 is about 749.7896992592.

The spelling of 421520217 in words is "four hundred twenty-one million, five hundred twenty thousand, two hundred seventeen".