1281225520 has 20 divisors (see below), whose sum is σ = 2978849520. Its totient is φ = 512490176.

The previous prime is 1281225509. The next prime is 1281225563. The reversal of 1281225520 is 255221821.

It is a tau number, because it is divible by the number of its divisors (20).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8007580 + ... + 8007739.

It is an arithmetic number, because the mean of its divisors is an integer number (148942476).

Almost surely, 2^1281225520 is an apocalyptic number.

1281225520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1281225520 is an abundant number, since it is smaller than the sum of its proper divisors (1697624000).

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

1281225520 is a wasteful number, since it uses less digits than its factorization.

1281225520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16015332 (or 16015326 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 28.

The square root of 1281225520 is about 35794.2107050847. The cubic root of 1281225520 is about 1086.1134541359.

It can be divided in two parts, 1281 and 225520, that added together give a triangular number (226801 = T₆₇₃).

The spelling of 1281225520 in words is "one billion, two hundred eighty-one million, two hundred twenty-five thousand, five hundred twenty".