1265211660 has 24 divisors (see below), whose sum is σ = 3542592816. Its totient is φ = 337389760.

The previous prime is 1265211637. The next prime is 1265211677. The reversal of 1265211660 is 661125621.

It is a Harshad number since it is a multiple of its sum of digits (30).

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, 10543371 + ... + 10543490.

It is an arithmetic number, because the mean of its divisors is an integer number (147608034).

Almost surely, 2^1265211660 is an apocalyptic number.

1265211660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1265211660 is an abundant number, since it is smaller than the sum of its proper divisors (2277381156).

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

1265211660 is a wasteful number, since it uses less digits than its factorization.

1265211660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21086873 (or 21086871 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 1265211660 is about 35569.8138876211. The cubic root of 1265211660 is about 1081.5694089707.

The spelling of 1265211660 in words is "one billion, two hundred sixty-five million, two hundred eleven thousand, six hundred sixty".