72406421 has 4 divisors (see below), whose sum is σ = 74742144. Its totient is φ = 70070700.

The previous prime is 72406403. The next prime is 72406429. The reversal of 72406421 is 12460427.

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: 12460427 = 7 ⋅1780061.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72406421 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 (72406429) 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, 1167815 + ... + 1167876.

It is an arithmetic number, because the mean of its divisors is an integer number (18685536).

Almost surely, 2^72406421 is an apocalyptic number.

It is an amenable number.

72406421 is a deficient number, since it is larger than the sum of its proper divisors (2335723).

72406421 is a wasteful number, since it uses less digits than its factorization.

72406421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2335722.

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 72406421 is about 8509.1962605172. The cubic root of 72406421 is about 416.7980646564.

Adding to 72406421 its reverse (12460427), we get a palindrome (84866848).

It can be divided in two parts, 72406 and 421, that added together give a palindrome (72827).

The spelling of 72406421 in words is "seventy-two million, four hundred six thousand, four hundred twenty-one".