75221421 has 16 divisors (see below), whose sum is σ = 109728768. Its totient is φ = 45457200.

The previous prime is 75221417. The next prime is 75221441. The reversal of 75221421 is 12412257.

It is not a de Polignac number, because 75221421 - 2² = 75221417 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 75221391 and 75221400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (75221411) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9006 + ... + 15216.

It is an arithmetic number, because the mean of its divisors is an integer number (6858048).

Almost surely, 2^75221421 is an apocalyptic number.

It is an amenable number.

75221421 is a deficient number, since it is larger than the sum of its proper divisors (34507347).

75221421 is a wasteful number, since it uses less digits than its factorization.

75221421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6592.

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

The square root of 75221421 is about 8673.0283638415. The cubic root of 75221421 is about 422.1309331441.

Adding to 75221421 its reverse (12412257), we get a palindrome (87633678).

The spelling of 75221421 in words is "seventy-five million, two hundred twenty-one thousand, four hundred twenty-one".