1221521255040 has 128 divisors (see below), whose sum is σ = 3901342838400. Its totient is φ = 325091151872.

The previous prime is 1221521254999. The next prime is 1221521255069. The reversal of 1221521255040 is 405521251221.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×1221521255040² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 1221521254989 and 1221521255007.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 333346 + ... + 1598174.

It is an arithmetic number, because the mean of its divisors is an integer number (30479240925).

Almost surely, 2^{1221521255040} is an apocalyptic number.

1221521255040 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 1221521255040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1950671419200).

1221521255040 is an abundant number, since it is smaller than the sum of its proper divisors (2679821583360).

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

1221521255040 is a wasteful number, since it uses less digits than its factorization.

1221521255040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1265354 (or 1265342 counting only the distinct ones).

The product of its (nonzero) digits is 8000, while the sum is 30.

The spelling of 1221521255040 in words is "one trillion, two hundred twenty-one billion, five hundred twenty-one million, two hundred fifty-five thousand, forty".