661796736 has 64 divisors (see below), whose sum is σ = 1765497600. Its totient is φ = 219645440.

The previous prime is 661796731. The next prime is 661796741. The reversal of 661796736 is 637697166.

661796736 = T₄₄₃ + T₄₄₄ + ... + T₁₅₉₄.

It is an interprime number because it is at equal distance from previous prime (661796731) and next prime (661796741).

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661796731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 88171 + ... + 95381.

It is an arithmetic number, because the mean of its divisors is an integer number (27585900).

Almost surely, 2^661796736 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 661796736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (882748800).

661796736 is an abundant number, since it is smaller than the sum of its proper divisors (1103700864).

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

661796736 is a wasteful number, since it uses less digits than its factorization.

661796736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7467 (or 7455 counting only the distinct ones).

The product of its digits is 1714608, while the sum is 51.

The square root of 661796736 is about 25725.4103174274. The cubic root of 661796736 is about 871.4481259584.

The spelling of 661796736 in words is "six hundred sixty-one million, seven hundred ninety-six thousand, seven hundred thirty-six".