1221890102505 has 24 divisors (see below), whose sum is σ = 2229413521920. Its totient is φ = 617376051360.

The previous prime is 1221890102501. The next prime is 1221890102519. The reversal of 1221890102505 is 5052010981221.

1221890102505 is a `hidden beast` number, since 122 + 18 + 9 + 0 + 10 + 2 + 505 = 666.

It is not a de Polignac number, because 1221890102505 - 2² = 1221890102501 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221890102505.

It is not an unprimeable number, because it can be changed into a prime (1221890102501) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 714554761 + ... + 714556470.

It is an arithmetic number, because the mean of its divisors is an integer number (92892230080).

Almost surely, 2^{1221890102505} is an apocalyptic number.

1221890102505 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221890102505 is a deficient number, since it is larger than the sum of its proper divisors (1007523419415).

1221890102505 is a wasteful number, since it uses less digits than its factorization.

1221890102505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1429111261 (or 1429111258 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 36.

The spelling of 1221890102505 in words is "one trillion, two hundred twenty-one billion, eight hundred ninety million, one hundred two thousand, five hundred five".