15216640 has 52 divisors (see below), whose sum is σ = 36564624. Its totient is φ = 6078464.

The previous prime is 15216623. The next prime is 15216647. The reversal of 15216640 is 4661251.

It is a super-2 number, since 2×15216640² = 463092265779200, which contains 22 as substring.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (15216647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20109 + ... + 20851.

Almost surely, 2^15216640 is an apocalyptic number.

15216640 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 15216640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18282312).

15216640 is an abundant number, since it is smaller than the sum of its proper divisors (21347984).

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

15216640 is an frugal number, since it uses more digits than its factorization.

15216640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 772 (or 750 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 15216640 is about 3900.8511891637. The cubic root of 15216640 is about 247.8028262813.

Adding to 15216640 its reverse (4661251), we get a palindrome (19877891).

The spelling of 15216640 in words is "fifteen million, two hundred sixteen thousand, six hundred forty".