661357536 has 192 divisors, whose sum is σ = 2073318912. Its totient is φ = 180652032.

The previous prime is 661357531. The next prime is 661357553. The reversal of 661357536 is 635753166.

It is a happy number.

661357536 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661357531) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1665690 + ... + 1666086.

It is an arithmetic number, because the mean of its divisors is an integer number (10798536).

Almost surely, 2^661357536 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 661357536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1036659456).

661357536 is an abundant number, since it is smaller than the sum of its proper divisors (1411961376).

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

661357536 is a wasteful number, since it uses less digits than its factorization.

661357536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 521 (or 513 counting only the distinct ones).

The product of its digits is 340200, while the sum is 42.

The square root of 661357536 is about 25716.8725936884. The cubic root of 661357536 is about 871.2553050636.

The spelling of 661357536 in words is "six hundred sixty-one million, three hundred fifty-seven thousand, five hundred thirty-six".