1216421523 has 32 divisors (see below), whose sum is σ = 1862784000. Its totient is φ = 784063008.

The previous prime is 1216421513. The next prime is 1216421527. The reversal of 1216421523 is 3251246121.

1216421523 is a `hidden beast` number, since 1 + 2 + 1 + 642 + 15 + 2 + 3 = 666.

It is not a de Polignac number, because 1216421523 - 2⁵ = 1216421491 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (1216421527) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 99553 + ... + 111101.

It is an arithmetic number, because the mean of its divisors is an integer number (58212000).

Almost surely, 2^1216421523 is an apocalyptic number.

1216421523 is a deficient number, since it is larger than the sum of its proper divisors (646362477).

1216421523 is a wasteful number, since it uses less digits than its factorization.

1216421523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11688 (or 11682 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 1216421523 is about 34877.2350251565. The cubic root of 1216421523 is about 1067.4839777700.

Adding to 1216421523 its reverse (3251246121), we get a palindrome (4467667644).

The spelling of 1216421523 in words is "one billion, two hundred sixteen million, four hundred twenty-one thousand, five hundred twenty-three".