1221453391650 has 96 divisors (see below), whose sum is σ = 3071854013760. Its totient is φ = 321164820480.

The previous prime is 1221453391643. The next prime is 1221453391657. The reversal of 1221453391650 is 561933541221.

It is an interprime number because it is at equal distance from previous prime (1221453391643) and next prime (1221453391657).

It is not an unprimeable number, because it can be changed into a prime (1221453391657) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3084661 + ... + 3458039.

It is an arithmetic number, because the mean of its divisors is an integer number (31998479310).

Almost surely, 2^{1221453391650} is an apocalyptic number.

1221453391650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221453391650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1535927006880).

1221453391650 is an abundant number, since it is smaller than the sum of its proper divisors (1850400622110).

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

1221453391650 is a wasteful number, since it uses less digits than its factorization.

1221453391650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373700 (or 373695 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 42.

The spelling of 1221453391650 in words is "one trillion, two hundred twenty-one billion, four hundred fifty-three million, three hundred ninety-one thousand, six hundred fifty".