1221445635264 has 784 divisors, whose sum is σ = 3933153050112. Its totient is φ = 375230693376.

The previous prime is 1221445635181. The next prime is 1221445635271. The reversal of 1221445635264 is 4625365441221.

It is a happy number.

1221445635264 is a `hidden beast` number, since 1 + 2 + 2 + 1 + 4 + 4 + 5 + 635 + 2 + 6 + 4 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 4752706624 + ... + 4752706880.

Almost surely, 2^{1221445635264} 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 1221445635264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1966576525056).

1221445635264 is an abundant number, since it is smaller than the sum of its proper divisors (2711707414848).

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

1221445635264 is a wasteful number, since it uses less digits than its factorization.

1221445635264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456 (or 431 counting only the distinct ones).

The product of its digits is 1382400, while the sum is 45.

The spelling of 1221445635264 in words is "one trillion, two hundred twenty-one billion, four hundred forty-five million, six hundred thirty-five thousand, two hundred sixty-four".