1221537252401 has 4 divisors (see below), whose sum is σ = 1221574080000. Its totient is φ = 1221500424804.

The previous prime is 1221537252379. The next prime is 1221537252451. The reversal of 1221537252401 is 1042527351221.

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 1221537252401 - 2³⁴ = 1204357383217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221537252451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18364001 + ... + 18430398.

It is an arithmetic number, because the mean of its divisors is an integer number (305393520000).

Almost surely, 2^{1221537252401} is an apocalyptic number.

It is an amenable number.

1221537252401 is a deficient number, since it is larger than the sum of its proper divisors (36827599).

1221537252401 is an equidigital number, since it uses as much as digits as its factorization.

1221537252401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36827598.

The product of its (nonzero) digits is 33600, while the sum is 35.

The spelling of 1221537252401 in words is "one trillion, two hundred twenty-one billion, five hundred thirty-seven million, two hundred fifty-two thousand, four hundred one".