19977728 has 20 divisors (see below), whose sum is σ = 39917460. Its totient is φ = 9988608.

The previous prime is 19977719. The next prime is 19977787. The reversal of 19977728 is 82777991.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18998 + ... + 20021.

It is an arithmetic number, because the mean of its divisors is an integer number (1995873).

Almost surely, 2^19977728 is an apocalyptic number.

It is an amenable number.

19977728 is a deficient number, since it is larger than the sum of its proper divisors (19939732).

19977728 is an frugal number, since it uses more digits than its factorization.

19977728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39037 (or 39021 counting only the distinct ones).

The product of its digits is 444528, while the sum is 50.

The square root of 19977728 is about 4469.6451760738. The cubic root of 19977728 is about 271.3409650526.

The spelling of 19977728 in words is "nineteen million, nine hundred seventy-seven thousand, seven hundred twenty-eight".