65621931606 has 288 divisors, whose sum is σ = 192259267200. Its totient is φ = 15949301760.

The previous prime is 65621931581. The next prime is 65621931629. The reversal of 65621931606 is 60613912656.

65621931606 is a `hidden beast` number, since 6 + 5 + 6 + 2 + 1 + 9 + 31 + 606 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 15297910 + ... + 15302198.

It is an arithmetic number, because the mean of its divisors is an integer number (667566900).

Almost surely, 2^65621931606 is an apocalyptic number.

65621931606 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 65621931606, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96129633600).

65621931606 is an abundant number, since it is smaller than the sum of its proper divisors (126637335594).

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

65621931606 is a wasteful number, since it uses less digits than its factorization.

65621931606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4424 (or 4414 counting only the distinct ones).

The product of its (nonzero) digits is 349920, while the sum is 45.

The spelling of 65621931606 in words is "sixty-five billion, six hundred twenty-one million, nine hundred thirty-one thousand, six hundred six".