1261628987 has 8 divisors (see below), whose sum is σ = 1293754176. Its totient is φ = 1229630472.

The previous prime is 1261628981. The next prime is 1261628989. The reversal of 1261628987 is 7898261621.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1261628987 - 2¹⁰ = 1261627963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1261628981) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11333 + ... + 51494.

It is an arithmetic number, because the mean of its divisors is an integer number (161719272).

Almost surely, 2^1261628987 is an apocalyptic number.

1261628987 is a deficient number, since it is larger than the sum of its proper divisors (32125189).

1261628987 is an equidigital number, since it uses as much as digits as its factorization.

1261628987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63337.

The product of its digits is 580608, while the sum is 50.

The square root of 1261628987 is about 35519.4170419504. The cubic root of 1261628987 is about 1080.5475581331.

The spelling of 1261628987 in words is "one billion, two hundred sixty-one million, six hundred twenty-eight thousand, nine hundred eighty-seven".