28018779940 has 24 divisors (see below), whose sum is σ = 59028645312. Its totient is φ = 11171472480.

The previous prime is 28018779871. The next prime is 28018779949. The reversal of 28018779940 is 4997781082.

It is a happy number.

It is a super-2 number, since 2×28018779940² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28018779949) 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, 2246094 + ... + 2258533.

It is an arithmetic number, because the mean of its divisors is an integer number (2459526888).

Almost surely, 2^28018779940 is an apocalyptic number.

28018779940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28018779940 is an abundant number, since it is smaller than the sum of its proper divisors (31009865372).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28018779940 is a wasteful number, since it uses less digits than its factorization.

28018779940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4504947 (or 4504945 counting only the distinct ones).

The product of its (nonzero) digits is 2032128, while the sum is 55.

The spelling of 28018779940 in words is "twenty-eight billion, eighteen million, seven hundred seventy-nine thousand, nine hundred forty".