1280621990 has 8 divisors (see below), whose sum is σ = 2305119600. Its totient is φ = 512248792.

The previous prime is 1280621941. The next prime is 1280621999. The reversal of 1280621990 is 991260821.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1280621999) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64031090 + ... + 64031109.

It is an arithmetic number, because the mean of its divisors is an integer number (288139950).

Almost surely, 2^1280621990 is an apocalyptic number.

1280621990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1280621990 is a deficient number, since it is larger than the sum of its proper divisors (1024497610).

1280621990 is a wasteful number, since it uses less digits than its factorization.

1280621990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128062206.

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 1280621990 is about 35785.7791587664. The cubic root of 1280621990 is about 1085.9428869729.

The spelling of 1280621990 in words is "one billion, two hundred eighty million, six hundred twenty-one thousand, nine hundred ninety".