1261979533 has 2 divisors, whose sum is σ = 1261979534. Its totient is φ = 1261979532.

The previous prime is 1261979503. The next prime is 1261979539. The reversal of 1261979533 is 3359791621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 692584489 + 569395044 = 26317^2 + 23862^2 .

It is an emirp because it is prime and its reverse (3359791621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1261979533 - 2¹³ = 1261971341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1261979539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630989766 + 630989767.

It is an arithmetic number, because the mean of its divisors is an integer number (630989767).

Almost surely, 2^1261979533 is an apocalyptic number.

It is an amenable number.

1261979533 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261979533 is an equidigital number, since it uses as much as digits as its factorization.

1261979533 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 306180, while the sum is 46.

The square root of 1261979533 is about 35524.3512678275. The cubic root of 1261979533 is about 1080.6476262598.

The spelling of 1261979533 in words is "one billion, two hundred sixty-one million, nine hundred seventy-nine thousand, five hundred thirty-three".