621509766691968 has 2304 divisors, whose sum is σ = 2516417820483840. Its totient is φ = 144816702750720.

The previous prime is 621509766691963. The next prime is 621509766691999. The reversal of 621509766691968 is 869196667905126.

It is not an unprimeable number, because it can be changed into a prime (621509766691963) by changing a digit.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 71135370096 + ... + 71135378832.

It is an arithmetic number, because the mean of its divisors is an integer number (1092195234585).

Almost surely, 2^{621509766691968} is an apocalyptic number.

621509766691968 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 621509766691968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1258208910241920).

621509766691968 is an abundant number, since it is smaller than the sum of its proper divisors (1894908053791872).

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

621509766691968 is a wasteful number, since it uses less digits than its factorization.

621509766691968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9115 (or 9093 counting only the distinct ones).

The product of its (nonzero) digits is 3174474240, while the sum is 81.

The spelling of 621509766691968 in words is "six hundred twenty-one trillion, five hundred nine billion, seven hundred sixty-six million, six hundred ninety-one thousand, nine hundred sixty-eight".