1221471195840 has 1792 divisors, whose sum is σ = 5287231488000. Its totient is φ = 259601448960.

The previous prime is 1221471195829. The next prime is 1221471195881. The reversal of 1221471195840 is 485911741221.

It is a happy number.

1221471195840 is a `hidden beast` number, since 1 + 2 + 21 + 47 + 1 + 1 + 9 + 584 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 8787562491 + ... + 8787562629.

It is an arithmetic number, because the mean of its divisors is an integer number (2950464000).

Almost surely, 2^{1221471195840} is an apocalyptic number.

1221471195840 is a gapful number since it is divisible by the number (10) 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 1221471195840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2643615744000).

1221471195840 is an abundant number, since it is smaller than the sum of its proper divisors (4065760292160).

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

1221471195840 is a wasteful number, since it uses less digits than its factorization.

1221471195840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355 (or 339 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 45.

The spelling of 1221471195840 in words is "one trillion, two hundred twenty-one billion, four hundred seventy-one million, one hundred ninety-five thousand, eight hundred forty".