1553660641561 has 8 divisors (see below), whose sum is σ = 1816905468224. Its totient is φ = 1300739141520.

The previous prime is 1553660641553. The next prime is 1553660641669. The reversal of 1553660641561 is 1651460663551.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1553660641561 - 2³ = 1553660641553 is a prime.

It is a super-2 number, since 2×1553660641561² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1553660641061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2580831330 + ... + 2580831931.

It is an arithmetic number, because the mean of its divisors is an integer number (227113183528).

Almost surely, 2^{1553660641561} is an apocalyptic number.

It is an amenable number.

1553660641561 is a deficient number, since it is larger than the sum of its proper divisors (263244826663).

1553660641561 is an equidigital number, since it uses as much as digits as its factorization.

1553660641561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5161663311.

The product of its (nonzero) digits is 1944000, while the sum is 49.

The spelling of 1553660641561 in words is "one trillion, five hundred fifty-three billion, six hundred sixty million, six hundred forty-one thousand, five hundred sixty-one".