1263821987 has 16 divisors (see below), whose sum is σ = 1333553760. Its totient is φ = 1196197632.

The previous prime is 1263821971. The next prime is 1263822017. The reversal of 1263821987 is 7891283621.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1263821987 - 2⁴ = 1263821971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1263821957) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 426503 + ... + 429455.

It is an arithmetic number, because the mean of its divisors is an integer number (83347110).

Almost surely, 2^1263821987 is an apocalyptic number.

1263821987 is a deficient number, since it is larger than the sum of its proper divisors (69731773).

1263821987 is a wasteful number, since it uses less digits than its factorization.

1263821987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3302.

The product of its digits is 290304, while the sum is 47.

The square root of 1263821987 is about 35550.2740777058. The cubic root of 1263821987 is about 1081.1732754005.

The spelling of 1263821987 in words is "one billion, two hundred sixty-three million, eight hundred twenty-one thousand, nine hundred eighty-seven".