266642640 has 240 divisors, whose sum is σ = 988168896. Its totient is φ = 63897600.

The previous prime is 266642633. The next prime is 266642669. The reversal of 266642640 is 46246662.

266642640 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (240).

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 = 266642595 and 266642604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1037392 + ... + 1037648.

Almost surely, 2^266642640 is an apocalyptic number.

266642640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 266642640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (494084448).

266642640 is an abundant number, since it is smaller than the sum of its proper divisors (721526256).

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

266642640 is a wasteful number, since it uses less digits than its factorization.

266642640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 418 (or 409 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 36.

The square root of 266642640 is about 16329.1959385635. The cubic root of 266642640 is about 643.6402579135.

The spelling of 266642640 in words is "two hundred sixty-six million, six hundred forty-two thousand, six hundred forty".