1221105256500 has 96 divisors (see below), whose sum is σ = 3556111104000. Its totient is φ = 325604937600.

The previous prime is 1221105256487. The next prime is 1221105256523. The reversal of 1221105256500 is 56525011221.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 36326701 + ... + 36360299.

It is an arithmetic number, because the mean of its divisors is an integer number (37042824000).

Almost surely, 2^{1221105256500} is an apocalyptic number.

1221105256500 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221105256500 is an abundant number, since it is smaller than the sum of its proper divisors (2335005847500).

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

1221105256500 is a wasteful number, since it uses less digits than its factorization.

1221105256500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57850 (or 57838 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 30.

The spelling of 1221105256500 in words is "one trillion, two hundred twenty-one billion, one hundred five million, two hundred fifty-six thousand, five hundred".