661206240 has 240 divisors, whose sum is σ = 2355324048. Its totient is φ = 174680064.

The previous prime is 661206239. The next prime is 661206253. The reversal of 661206240 is 42602166.

It is a happy number.

661206240 is a `hidden beast` number, since 6 + 612 + 0 + 6 + 2 + 40 = 666.

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

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 2112324 + ... + 2112636.

Almost surely, 2^661206240 is an apocalyptic number.

661206240 is a gapful number since it is divisible by the number (60) 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 661206240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1177662024).

661206240 is an abundant number, since it is smaller than the sum of its proper divisors (1694117808).

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

661206240 is a wasteful number, since it uses less digits than its factorization.

661206240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 503 (or 486 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 661206240 is about 25713.9308546943. The cubic root of 661206240 is about 871.1888621849.

The spelling of 661206240 in words is "six hundred sixty-one million, two hundred six thousand, two hundred forty".