1216253445 has 32 divisors (see below), whose sum is σ = 2127772800. Its totient is φ = 588349440.

The previous prime is 1216253443. The next prime is 1216253449. The reversal of 1216253445 is 5443526121.

It is not a de Polignac number, because 1216253445 - 2¹ = 1216253443 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216253443) 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, 65877 + ... + 82293.

It is an arithmetic number, because the mean of its divisors is an integer number (66492900).

Almost surely, 2^1216253445 is an apocalyptic number.

1216253445 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1216253445 is a deficient number, since it is larger than the sum of its proper divisors (911519355).

1216253445 is a wasteful number, since it uses less digits than its factorization.

1216253445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16885.

The product of its digits is 28800, while the sum is 33.

The square root of 1216253445 is about 34874.8253759069. The cubic root of 1216253445 is about 1067.4348092778.

Adding to 1216253445 its reverse (5443526121), we get a palindrome (6659779566).

The spelling of 1216253445 in words is "one billion, two hundred sixteen million, two hundred fifty-three thousand, four hundred forty-five".