1221816496464 has 480 divisors, whose sum is σ = 3787697849600. Its totient is φ = 376782658560.

The previous prime is 1221816496463. The next prime is 1221816496477. The reversal of 1221816496464 is 4646946181221.

1221816496464 is a `hidden beast` number, since 1 + 2 + 2 + 18 + 164 + 9 + 6 + 464 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 1221816496464.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221816496463) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1936317429 + ... + 1936318059.

Almost surely, 2^{1221816496464} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221816496464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1893848924800).

1221816496464 is an abundant number, since it is smaller than the sum of its proper divisors (2565881353136).

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

1221816496464 is a wasteful number, since it uses less digits than its factorization.

1221816496464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 960 (or 925 counting only the distinct ones).

The product of its digits is 3981312, while the sum is 54.

The spelling of 1221816496464 in words is "one trillion, two hundred twenty-one billion, eight hundred sixteen million, four hundred ninety-six thousand, four hundred sixty-four".