1266722640 has 60 divisors (see below), whose sum is σ = 4254079284. Its totient is φ = 337792512.

The previous prime is 1266722621. The next prime is 1266722641. The reversal of 1266722640 is 462276621.

1266722640 is a `hidden beast` number, since 1 + 2 + 6 + 6 + 7 + 2 + 2 + 640 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 253191744 + 1013530896 = 15912^2 + 31836^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1266722595 and 1266722604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1266722641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 878949 + ... + 880388.

Almost surely, 2^1266722640 is an apocalyptic number.

1266722640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1266722640 is an abundant number, since it is smaller than the sum of its proper divisors (2987356644).

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

1266722640 is a wasteful number, since it uses less digits than its factorization.

1266722640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1759356 (or 1759347 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The square root of 1266722640 is about 35591.0471888648. The cubic root of 1266722640 is about 1081.9997927208. Note that the first 3 decimals are identical.

The spelling of 1266722640 in words is "one billion, two hundred sixty-six million, seven hundred twenty-two thousand, six hundred forty".