661216088 has 64 divisors (see below), whose sum is σ = 1437095520. Its totient is φ = 282470400.

The previous prime is 661216079. The next prime is 661216091. The reversal of 661216088 is 880612166.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 104783 + ... + 110913.

Almost surely, 2^661216088 is an apocalyptic number.

661216088 is a gapful number since it is divisible by the number (68) 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 661216088, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (718547760).

661216088 is an abundant number, since it is smaller than the sum of its proper divisors (775879432).

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

661216088 is a wasteful number, since it uses less digits than its factorization.

661216088 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6228 (or 6224 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 661216088 is about 25714.1223455128. The cubic root of 661216088 is about 871.1931873232.

The spelling of 661216088 in words is "six hundred sixty-one million, two hundred sixteen thousand, eighty-eight".