1221664449785 has 16 divisors (see below), whose sum is σ = 1605525122880. Its totient is φ = 886861490880.

The previous prime is 1221664449767. The next prime is 1221664449791. The reversal of 1221664449785 is 5879444661221.

It is a de Polignac number, because none of the positive numbers 2^k-1221664449785 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (59).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 159274451 + ... + 159282120.

It is an arithmetic number, because the mean of its divisors is an integer number (100345320180).

Almost surely, 2^{1221664449785} is an apocalyptic number.

It is an amenable number.

1221664449785 is a deficient number, since it is larger than the sum of its proper divisors (383860673095).

1221664449785 is a wasteful number, since it uses less digits than its factorization.

1221664449785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318556648.

The product of its digits is 23224320, while the sum is 59.

The spelling of 1221664449785 in words is "one trillion, two hundred twenty-one billion, six hundred sixty-four million, four hundred forty-nine thousand, seven hundred eighty-five".