1261563353601 has 4 divisors (see below), whose sum is σ = 1682084471472. Its totient is φ = 841042235732.

The previous prime is 1261563353543. The next prime is 1261563353621. The reversal of 1261563353601 is 1063533651621.

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 1261563353601 - 2⁶ = 1261563353537 is a prime.

It is a super-4 number, since 4×1261563353601⁴ (a number of 50 digits) contains 4444 as substring.

It is not an unprimeable number, because it can be changed into a prime (1261563353621) 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, 210260558931 + ... + 210260558936.

It is an arithmetic number, because the mean of its divisors is an integer number (420521117868).

Almost surely, 2^{1261563353601} is an apocalyptic number.

It is an amenable number.

1261563353601 is a deficient number, since it is larger than the sum of its proper divisors (420521117871).

1261563353601 is an equidigital number, since it uses as much as digits as its factorization.

1261563353601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 420521117870.

The product of its (nonzero) digits is 291600, while the sum is 42.

The spelling of 1261563353601 in words is "one trillion, two hundred sixty-one billion, five hundred sixty-three million, three hundred fifty-three thousand, six hundred one".