28440146721 has 8 divisors (see below), whose sum is σ = 43337366464. Its totient is φ = 16251512400.

The previous prime is 28440146717. The next prime is 28440146731. The reversal of 28440146721 is 12764104482.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28440146721 - 2² = 28440146717 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28440146721.

It is not an unprimeable number, because it can be changed into a prime (28440146731) 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 in 7 ways as a sum of consecutive naturals, for example, 677146330 + ... + 677146371.

It is an arithmetic number, because the mean of its divisors is an integer number (5417170808).

Almost surely, 2^28440146721 is an apocalyptic number.

28440146721 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28440146721 is a deficient number, since it is larger than the sum of its proper divisors (14897219743).

28440146721 is a wasteful number, since it uses less digits than its factorization.

28440146721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1354292711.

The product of its (nonzero) digits is 86016, while the sum is 39.

The spelling of 28440146721 in words is "twenty-eight billion, four hundred forty million, one hundred forty-six thousand, seven hundred twenty-one".