1216540528 has 20 divisors (see below), whose sum is σ = 2693768560. Its totient is φ = 521374464.

The previous prime is 1216540489. The next prime is 1216540571. The reversal of 1216540528 is 8250456121.

It is a happy number.

It is a super-3 number, since 3×1216540528³ (a number of 28 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1216540493 and 1216540502.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5430873 + ... + 5431096.

It is an arithmetic number, because the mean of its divisors is an integer number (134688428).

Almost surely, 2^1216540528 is an apocalyptic number.

It is an amenable number.

1216540528 is an abundant number, since it is smaller than the sum of its proper divisors (1477228032).

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

1216540528 is a wasteful number, since it uses less digits than its factorization.

1216540528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10861984 (or 10861978 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 34.

The square root of 1216540528 is about 34878.9410389708. The cubic root of 1216540528 is about 1067.5187880135.

Adding to 1216540528 its reverse (8250456121), we get a palindrome (9466996649).

The spelling of 1216540528 in words is "one billion, two hundred sixteen million, five hundred forty thousand, five hundred twenty-eight".