1216235520 has 384 divisors, whose sum is σ = 4457980800. Its totient is φ = 314376192.

The previous prime is 1216235519. The next prime is 1216235551. The reversal of 1216235520 is 255326121.

It is a happy number.

1216235520 is a `hidden beast` number, since 12 + 1 + 623 + 5 + 5 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14653399 + ... + 14653481.

It is an arithmetic number, because the mean of its divisors is an integer number (11609325).

Almost surely, 2^1216235520 is an apocalyptic number.

1216235520 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 1216235520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2228990400).

1216235520 is an abundant number, since it is smaller than the sum of its proper divisors (3241745280).

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

1216235520 is an equidigital number, since it uses as much as digits as its factorization.

1216235520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172 (or 146 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 1216235520 is about 34874.5683844259. The cubic root of 1216235520 is about 1067.4295653425.

The spelling of 1216235520 in words is "one billion, two hundred sixteen million, two hundred thirty-five thousand, five hundred twenty".