72428666 has 4 divisors (see below), whose sum is σ = 108643002. Its totient is φ = 36214332.

The previous prime is 72428659. The next prime is 72428669. The reversal of 72428666 is 66682427.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 71048041 + 1380625 = 8429^2 + 1175^2 .

It is not an unprimeable number, because it can be changed into a prime (72428669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18107165 + ... + 18107168.

Almost surely, 2^72428666 is an apocalyptic number.

72428666 is a deficient number, since it is larger than the sum of its proper divisors (36214336).

72428666 is a wasteful number, since it uses less digits than its factorization.

72428666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36214335.

The product of its digits is 193536, while the sum is 41.

The square root of 72428666 is about 8510.5032753651. The cubic root of 72428666 is about 416.8407437608.

The spelling of 72428666 in words is "seventy-two million, four hundred twenty-eight thousand, six hundred sixty-six".