28720634 has 4 divisors (see below), whose sum is σ = 43080954. Its totient is φ = 14360316.

The previous prime is 28720613. The next prime is 28720639. The reversal of 28720634 is 43602782.

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., 17181025 + 11539609 = 4145^2 + 3397^2 .

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 28720634.

It is not an unprimeable number, because it can be changed into a prime (28720639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7180157 + ... + 7180160.

Almost surely, 2^28720634 is an apocalyptic number.

28720634 is a deficient number, since it is larger than the sum of its proper divisors (14360320).

28720634 is a wasteful number, since it uses less digits than its factorization.

28720634 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14360319.

The product of its (nonzero) digits is 16128, while the sum is 32.

The square root of 28720634 is about 5359.1635541379. The cubic root of 28720634 is about 306.2419448666.

The spelling of 28720634 in words is "twenty-eight million, seven hundred twenty thousand, six hundred thirty-four".