15780640 has 96 divisors (see below), whose sum is σ = 40824000. Its totient is φ = 5741568.

The previous prime is 15780637. The next prime is 15780647. The reversal of 15780640 is 4608751.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15780647) 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, 88071 + ... + 88249.

It is an arithmetic number, because the mean of its divisors is an integer number (425250).

Almost surely, 2^15780640 is an apocalyptic number.

15780640 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 15780640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20412000).

15780640 is an abundant number, since it is smaller than the sum of its proper divisors (25043360).

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

15780640 is a wasteful number, since it uses less digits than its factorization.

15780640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242 (or 234 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 15780640 is about 3972.4853681291. The cubic root of 15780640 is about 250.8273390203.

The spelling of 15780640 in words is "fifteen million, seven hundred eighty thousand, six hundred forty".