691023771648 has 1152 divisors, whose sum is σ = 2593334016000. Its totient is φ = 180592312320.

The previous prime is 691023771589. The next prime is 691023771677. The reversal of 691023771648 is 846177320196.

691023771648 is a `hidden beast` number, since 6 + 9 + 102 + 377 + 164 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (1152).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 691023771594 and 691023771603.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1595897640 + ... + 1595898072.

It is an arithmetic number, because the mean of its divisors is an integer number (2251158000).

Almost surely, 2^691023771648 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 691023771648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1296667008000).

691023771648 is an abundant number, since it is smaller than the sum of its proper divisors (1902310244352).

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

691023771648 is a wasteful number, since it uses less digits than its factorization.

691023771648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 528 (or 495 counting only the distinct ones).

The product of its (nonzero) digits is 3048192, while the sum is 54.

The spelling of 691023771648 in words is "six hundred ninety-one billion, twenty-three million, seven hundred seventy-one thousand, six hundred forty-eight".