1263921601 has 4 divisors (see below), whose sum is σ = 1264005252. Its totient is φ = 1263837952.

The previous prime is 1263921577. The next prime is 1263921619. The reversal of 1263921601 is 1061293621.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 935442225 + 328479376 = 30585^2 + 18124^2 .

It is a cyclic number.

It is not a de Polignac number, because 1263921601 - 2²¹ = 1261824449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1263921641) 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, 12136 + ... + 51721.

It is an arithmetic number, because the mean of its divisors is an integer number (316001313).

Almost surely, 2^1263921601 is an apocalyptic number.

It is an amenable number.

1263921601 is a deficient number, since it is larger than the sum of its proper divisors (83651).

1263921601 is an equidigital number, since it uses as much as digits as its factorization.

1263921601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83650.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 1263921601 is about 35551.6750800859. The cubic root of 1263921601 is about 1081.2016805520.

The spelling of 1263921601 in words is "one billion, two hundred sixty-three million, nine hundred twenty-one thousand, six hundred one".