15778980 has 108 divisors (see below), whose sum is σ = 55708380. Its totient is φ = 3604608.

The previous prime is 15778967. The next prime is 15778999. The reversal of 15778980 is 8987751.

It can be written as a sum of positive squares in 2 ways, for example, as 11009124 + 4769856 = 3318^2 + 2184^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 7926 + ... + 9714.

Almost surely, 2^15778980 is an apocalyptic number.

15778980 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 15778980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27854190).

15778980 is an abundant number, since it is smaller than the sum of its proper divisors (39929400).

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

15778980 is a wasteful number, since it uses less digits than its factorization.

15778980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1818 (or 1806 counting only the distinct ones).

The product of its (nonzero) digits is 141120, while the sum is 45.

The square root of 15778980 is about 3972.2764254266. The cubic root of 15778980 is about 250.8185436866.

Adding to 15778980 its product of nonzero digits (141120), we get a square (15920100 = 3990²).

The spelling of 15778980 in words is "fifteen million, seven hundred seventy-eight thousand, nine hundred eighty".