1281667656 has 32 divisors (see below), whose sum is σ = 3251996640. Its totient is φ = 420845568.

The previous prime is 1281667633. The next prime is 1281667661. The reversal of 1281667656 is 6567661821.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 396921 + ... + 400136.

It is an arithmetic number, because the mean of its divisors is an integer number (101624895).

Almost surely, 2^1281667656 is an apocalyptic number.

It is an amenable number.

1281667656 is an abundant number, since it is smaller than the sum of its proper divisors (1970328984).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1281667656 is a wasteful number, since it uses less digits than its factorization.

1281667656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 797133 (or 797129 counting only the distinct ones).

The product of its digits is 725760, while the sum is 48.

The square root of 1281667656 is about 35800.3862548995. The cubic root of 1281667656 is about 1086.2383748005.

The spelling of 1281667656 in words is "one billion, two hundred eighty-one million, six hundred sixty-seven thousand, six hundred fifty-six".