1221551644260 has 24 divisors (see below), whose sum is σ = 3420344604096. Its totient is φ = 325747105120.

The previous prime is 1221551644217. The next prime is 1221551644301. The reversal of 1221551644260 is 624461551221.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10179596976 + ... + 10179597095.

It is an arithmetic number, because the mean of its divisors is an integer number (142514358504).

Almost surely, 2^{1221551644260} is an apocalyptic number.

1221551644260 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221551644260 is an abundant number, since it is smaller than the sum of its proper divisors (2198792959836).

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

1221551644260 is a wasteful number, since it uses less digits than its factorization.

1221551644260 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20359194083 (or 20359194081 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 39.

The spelling of 1221551644260 in words is "one trillion, two hundred twenty-one billion, five hundred fifty-one million, six hundred forty-four thousand, two hundred sixty".