1265516616 has 288 divisors, whose sum is σ = 4131466560. Its totient is φ = 316173312.

The previous prime is 1265516591. The next prime is 1265516653. The reversal of 1265516616 is 6166155621.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 23877646 + ... + 23877698.

It is an arithmetic number, because the mean of its divisors is an integer number (14345370).

Almost surely, 2^1265516616 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1265516616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2065733280).

1265516616 is an abundant number, since it is smaller than the sum of its proper divisors (2865949944).

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

1265516616 is a wasteful number, since it uses less digits than its factorization.

1265516616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153 (or 107 counting only the distinct ones).

The product of its digits is 64800, while the sum is 39.

The square root of 1265516616 is about 35574.1003540497. The cubic root of 1265516616 is about 1081.6562994610.

The spelling of 1265516616 in words is "one billion, two hundred sixty-five million, five hundred sixteen thousand, six hundred sixteen".