1221404401653 has 4 divisors (see below), whose sum is σ = 1628539202208. Its totient is φ = 814269601100.

The previous prime is 1221404401649. The next prime is 1221404401703. The reversal of 1221404401653 is 3561044041221.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1221404401653 - 2² = 1221404401649 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221404481653) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 203567400273 + ... + 203567400278.

It is an arithmetic number, because the mean of its divisors is an integer number (407134800552).

Almost surely, 2^{1221404401653} is an apocalyptic number.

It is an amenable number.

1221404401653 is a deficient number, since it is larger than the sum of its proper divisors (407134800555).

1221404401653 is an equidigital number, since it uses as much as digits as its factorization.

1221404401653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407134800554.

The product of its (nonzero) digits is 23040, while the sum is 33.

Adding to 1221404401653 its reverse (3561044041221), we get a palindrome (4782448442874).

The spelling of 1221404401653 in words is "one trillion, two hundred twenty-one billion, four hundred four million, four hundred one thousand, six hundred fifty-three".