18777640 has 64 divisors (see below), whose sum is σ = 48672000. Its totient is φ = 6386688.

The previous prime is 18777623. The next prime is 18777641. The reversal of 18777640 is 4677781.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 18777593 and 18777602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18777641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55552 + ... + 55888.

It is an arithmetic number, because the mean of its divisors is an integer number (760500).

Almost surely, 2^18777640 is an apocalyptic number.

18777640 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 18777640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24336000).

18777640 is an abundant number, since it is smaller than the sum of its proper divisors (29894360).

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

18777640 is a wasteful number, since it uses less digits than its factorization.

18777640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 554 (or 550 counting only the distinct ones).

The product of its (nonzero) digits is 65856, while the sum is 40.

The square root of 18777640 is about 4333.3174358683. The cubic root of 18777640 is about 265.7951199044.

The spelling of 18777640 in words is "eighteen million, seven hundred seventy-seven thousand, six hundred forty".