921566421 has 12 divisors (see below), whose sum is σ = 1332569472. Its totient is φ = 613723176.

The previous prime is 921566383. The next prime is 921566473. The reversal of 921566421 is 124665129.

921566421 is a `hidden beast` number, since 9 + 2 + 1 + 5 + 6 + 642 + 1 = 666.

It is not a de Polignac number, because 921566421 - 2¹⁰ = 921565397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (921566221) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 45541 + ... + 62586.

It is an arithmetic number, because the mean of its divisors is an integer number (111047456).

Almost surely, 2^921566421 is an apocalyptic number.

It is an amenable number.

921566421 is a deficient number, since it is larger than the sum of its proper divisors (411003051).

921566421 is a wasteful number, since it uses less digits than its factorization.

921566421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109080 (or 109077 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 921566421 is about 30357.3124798622. The cubic root of 921566421 is about 973.1405000359.

The spelling of 921566421 in words is "nine hundred twenty-one million, five hundred sixty-six thousand, four hundred twenty-one".