1221257553145 has 16 divisors (see below), whose sum is σ = 1676821880448. Its totient is φ = 836456561280.

The previous prime is 1221257553127. The next prime is 1221257553163. The reversal of 1221257553145 is 5413557521221.

It is an interprime number because it is at equal distance from previous prime (1221257553127) and next prime (1221257553163).

It is not a de Polignac number, because 1221257553145 - 2¹³ = 1221257544953 is a prime.

It is a super-2 number, since 2×1221257553145² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

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, 20327691 + ... + 20387680.

It is an arithmetic number, because the mean of its divisors is an integer number (104801367528).

Almost surely, 2^{1221257553145} is an apocalyptic number.

It is an amenable number.

1221257553145 is a deficient number, since it is larger than the sum of its proper divisors (455564327303).

1221257553145 is an equidigital number, since it uses as much as digits as its factorization.

1221257553145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40716240.

The product of its digits is 420000, while the sum is 43.

The spelling of 1221257553145 in words is "one trillion, two hundred twenty-one billion, two hundred fifty-seven million, five hundred fifty-three thousand, one hundred forty-five".