1221042723264 has 1344 divisors, whose sum is σ = 4601959677952. Its totient is φ = 300987187200.

The previous prime is 1221042723259. The next prime is 1221042723269. The reversal of 1221042723264 is 4623272401221.

1221042723264 is a `hidden beast` number, since 1 + 22 + 104 + 272 + 3 + 264 = 666.

It is an interprime number because it is at equal distance from previous prime (1221042723259) and next prime (1221042723269).

It is a tau number, because it is divible by the number of its divisors (1344).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221042723269) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 9614509569 + ... + 9614509695.

Almost surely, 2^{1221042723264} is an apocalyptic number.

1221042723264 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221042723264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2300979838976).

1221042723264 is an abundant number, since it is smaller than the sum of its proper divisors (3380916954688).

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

1221042723264 is a wasteful number, since it uses less digits than its factorization.

1221042723264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 354 (or 341 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 36.

The spelling of 1221042723264 in words is "one trillion, two hundred twenty-one billion, forty-two million, seven hundred twenty-three thousand, two hundred sixty-four".