28418721644 has 24 divisors (see below), whose sum is σ = 50806737408. Its totient is φ = 13902699600.

The previous prime is 28418721641. The next prime is 28418721649. The reversal of 28418721644 is 44612781482.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is not an unprimeable number, because it can be changed into a prime (28418721641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 629219 + ... + 672869.

It is an arithmetic number, because the mean of its divisors is an integer number (2116947392).

Almost surely, 2^28418721644 is an apocalyptic number.

It is an amenable number.

28418721644 is a deficient number, since it is larger than the sum of its proper divisors (22388015764).

28418721644 is a wasteful number, since it uses less digits than its factorization.

28418721644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47165 (or 47163 counting only the distinct ones).

The product of its digits is 688128, while the sum is 47.

The spelling of 28418721644 in words is "twenty-eight billion, four hundred eighteen million, seven hundred twenty-one thousand, six hundred forty-four".