421165921 has 4 divisors (see below), whose sum is σ = 459453744. Its totient is φ = 382878100.

The previous prime is 421165853. The next prime is 421165963. The reversal of 421165921 is 129561124.

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 not a de Polignac number, because 421165921 - 2⁷ = 421165793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (421162921) 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, 19143895 + ... + 19143916.

It is an arithmetic number, because the mean of its divisors is an integer number (114863436).

Almost surely, 2^421165921 is an apocalyptic number.

It is an amenable number.

421165921 is a deficient number, since it is larger than the sum of its proper divisors (38287823).

421165921 is a wasteful number, since it uses less digits than its factorization.

421165921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38287822.

The product of its digits is 4320, while the sum is 31.

The square root of 421165921 is about 20522.3273777610. The cubic root of 421165921 is about 749.5795693986.

The spelling of 421165921 in words is "four hundred twenty-one million, one hundred sixty-five thousand, nine hundred twenty-one".