1221679579392 has 648 divisors, whose sum is σ = 3811481037000. Its totient is φ = 375800463360.

The previous prime is 1221679579381. The next prime is 1221679579403. The reversal of 1221679579392 is 2939759761221.

1221679579392 is a `hidden beast` number, since 1 + 2 + 21 + 6 + 7 + 9 + 579 + 39 + 2 = 666.

It is an interprime number because it is at equal distance from previous prime (1221679579381) and next prime (1221679579403).

It can be written as a sum of positive squares in 12 ways, for example, as 998048952576 + 223630626816 = 999024^2 + 472896^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 8199191734 + ... + 8199191882.

Almost surely, 2^{1221679579392} is an apocalyptic number.

1221679579392 is a gapful number since it is divisible by the number (12) 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 1221679579392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1905740518500).

1221679579392 is an abundant number, since it is smaller than the sum of its proper divisors (2589801457608).

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

1221679579392 is a wasteful number, since it uses less digits than its factorization.

1221679579392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355 (or 297 counting only the distinct ones).

The product of its digits is 25719120, while the sum is 63.

The spelling of 1221679579392 in words is "one trillion, two hundred twenty-one billion, six hundred seventy-nine million, five hundred seventy-nine thousand, three hundred ninety-two".