1218021696 has 42 divisors (see below), whose sum is σ = 3491240922. Its totient is φ = 406007040.

The previous prime is 1218021683. The next prime is 1218021697. The reversal of 1218021696 is 6961208121.

It can be written as a sum of positive squares in only one way, i.e., 836366400 + 381655296 = 28920^2 + 19536^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 1218021696.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1218021697) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1056735 + ... + 1057886.

Almost surely, 2^1218021696 is an apocalyptic number.

1218021696 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1218021696 is an abundant number, since it is smaller than the sum of its proper divisors (2273219226).

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

1218021696 is a wasteful number, since it uses less digits than its factorization.

1218021696 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2114639 (or 2114626 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 1218021696 is about 34900.1675640677. The cubic root of 1218021696 is about 1067.9518557601.

The spelling of 1218021696 in words is "one billion, two hundred eighteen million, twenty-one thousand, six hundred ninety-six".