1284886921 has 6 divisors (see below), whose sum is σ = 1290777422. Its totient is φ = 1279001280.

The previous prime is 1284886879. The next prime is 1284886931. The reversal of 1284886921 is 1296884821.

It can be written as a sum of positive squares in 3 ways, for example, as 777015625 + 507871296 = 27875^2 + 22536^2 .

It is not a de Polignac number, because 1284886921 - 2⁹ = 1284886409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1284886931) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 555315 + ... + 557623.

Almost surely, 2^1284886921 is an apocalyptic number.

It is an amenable number.

1284886921 is a deficient number, since it is larger than the sum of its proper divisors (5890501).

1284886921 is an frugal number, since it uses more digits than its factorization.

1284886921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4859 (or 2550 counting only the distinct ones).

The product of its digits is 442368, while the sum is 49.

The square root of 1284886921 is about 35845.3193736644. The cubic root of 1284886921 is about 1087.1470777289.

The spelling of 1284886921 in words is "one billion, two hundred eighty-four million, eight hundred eighty-six thousand, nine hundred twenty-one".