1261023151 has 4 divisors (see below), whose sum is σ = 1270095400. Its totient is φ = 1251950904.

The previous prime is 1261023149. The next prime is 1261023157. The reversal of 1261023151 is 1513201621.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 1261023151 - 2¹ = 1261023149 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261023157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4535916 + ... + 4536193.

It is an arithmetic number, because the mean of its divisors is an integer number (317523850).

Almost surely, 2^1261023151 is an apocalyptic number.

1261023151 is a deficient number, since it is larger than the sum of its proper divisors (9072249).

1261023151 is an equidigital number, since it uses as much as digits as its factorization.

1261023151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9072248.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 1261023151 is about 35510.8877810736. The cubic root of 1261023151 is about 1080.3745702921.

Adding to 1261023151 its reverse (1513201621), we get a palindrome (2774224772).

The spelling of 1261023151 in words is "one billion, two hundred sixty-one million, twenty-three thousand, one hundred fifty-one".