921421 has 4 divisors (see below), whose sum is σ = 925344. Its totient is φ = 917500.

The previous prime is 921409. The next prime is 921457. The reversal of 921421 is 124129.

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 an emirpimes, since its reverse is a distinct semiprime: 124129 = 101 ⋅1229.

It is a cyclic number.

It is not a de Polignac number, because 921421 - 2⁷ = 921293 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 (921491) 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 in 3 ways as a sum of consecutive naturals, for example, 1585 + ... + 2086.

It is an arithmetic number, because the mean of its divisors is an integer number (231336).

2⁹²¹⁴²¹ is an apocalyptic number.

It is an amenable number.

921421 is a deficient number, since it is larger than the sum of its proper divisors (3923).

921421 is a wasteful number, since it uses less digits than its factorization.

921421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3922.

The product of its digits is 144, while the sum is 19.

The square root of 921421 is about 959.9067663060. The cubic root of 921421 is about 97.3089310921.

The spelling of 921421 in words is "nine hundred twenty-one thousand, four hundred twenty-one".