75421 has 4 divisors (see below), whose sum is σ = 76000. Its totient is φ = 74844.

The previous prime is 75407. The next prime is 75431. The reversal of 75421 is 12457.

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 75421 - 2⁵ = 75389 is a prime.

It is a Duffinian number.

75421 is a lucky number.

It is a plaindrome in base 16.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (75401) 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, 10 + ... + 388.

It is an arithmetic number, because the mean of its divisors is an integer number (19000).

2⁷⁵⁴²¹ is an apocalyptic number.

It is an amenable number.

75421 is a deficient number, since it is larger than the sum of its proper divisors (579).

75421 is a wasteful number, since it uses less digits than its factorization.

75421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 578.

The product of its digits is 280, while the sum is 19.

The square root of 75421 is about 274.6288404374. The cubic root of 75421 is about 42.2503938901.

Adding to 75421 its reverse (12457), we get a palindrome (87878).

It can be divided in two parts, 75 and 421, that added together give a triangular number (496 = T₃₁).

The spelling of 75421 in words is "seventy-five thousand, four hundred twenty-one".