1261977601 has 4 divisors (see below), whose sum is σ = 1305494100. Its totient is φ = 1218461104.

The previous prime is 1261977571. The next prime is 1261977637. The reversal of 1261977601 is 1067791621.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 463971600 + 798006001 = 21540^2 + 28249^2 .

It is a cyclic number.

It is not a de Polignac number, because 1261977601 - 2¹¹ = 1261975553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1261977641) 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, 21758206 + ... + 21758263.

It is an arithmetic number, because the mean of its divisors is an integer number (326373525).

Almost surely, 2^1261977601 is an apocalyptic number.

It is an amenable number.

1261977601 is a deficient number, since it is larger than the sum of its proper divisors (43516499).

1261977601 is an equidigital number, since it uses as much as digits as its factorization.

1261977601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43516498.

The product of its (nonzero) digits is 31752, while the sum is 40.

The square root of 1261977601 is about 35524.3240752023. The cubic root of 1261977601 is about 1080.6470747949.

The spelling of 1261977601 in words is "one billion, two hundred sixty-one million, nine hundred seventy-seven thousand, six hundred one".