18977980 has 48 divisors (see below), whose sum is σ = 45803520. Its totient is φ = 6470208.

The previous prime is 18977963. The next prime is 18978019. The reversal of 18977980 is 8977981.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 39381 + ... + 39859.

It is an arithmetic number, because the mean of its divisors is an integer number (954240).

Almost surely, 2^18977980 is an apocalyptic number.

18977980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18977980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22901760).

18977980 is an abundant number, since it is smaller than the sum of its proper divisors (26825540).

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

18977980 is a wasteful number, since it uses less digits than its factorization.

18977980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 778 (or 776 counting only the distinct ones).

The product of its (nonzero) digits is 254016, while the sum is 49.

The square root of 18977980 is about 4356.3723440496. The cubic root of 18977980 is about 266.7370404544.

Subtracting from 18977980 its reverse (8977981), we obtain a palindrome (9999999).

The spelling of 18977980 in words is "eighteen million, nine hundred seventy-seven thousand, nine hundred eighty".