1221723942640 has 20 divisors (see below), whose sum is σ = 2840508166824. Its totient is φ = 488689577024.

The previous prime is 1221723942623. The next prime is 1221723942661. The reversal of 1221723942640 is 462493271221.

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7635774562 + ... + 7635774721.

Almost surely, 2^{1221723942640} is an apocalyptic number.

1221723942640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221723942640 is an abundant number, since it is smaller than the sum of its proper divisors (1618784224184).

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

1221723942640 is a wasteful number, since it uses less digits than its factorization.

1221723942640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15271549296 (or 15271549290 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 43.

The spelling of 1221723942640 in words is "one trillion, two hundred twenty-one billion, seven hundred twenty-three million, nine hundred forty-two thousand, six hundred forty".