68821750921 has 27 divisors (see below), whose sum is σ = 88023423117. Its totient is φ = 53611598040.

The previous prime is 68821750901. The next prime is 68821750927. The reversal of 68821750921 is 12905712886.

It is a happy number.

The square root of 68821750921 is 262339.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 68821750921 - 2¹⁷ = 68821619849 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is not an unprimeable number, because it can be changed into a prime (68821750927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 20198400 + ... + 20201806.

Almost surely, 2^68821750921 is an apocalyptic number.

68821750921 is the 262339-th square number.

68821750921 is the 131170-th centered octagonal number.

It is an amenable number.

68821750921 is a deficient number, since it is larger than the sum of its proper divisors (19201672196).

68821750921 is an frugal number, since it uses more digits than its factorization.

68821750921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6850 (or 3425 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 49.

Multiplying 68821750921 by its sum of digits (49), we get a square (3372265795129 = 1836373²).

68821750921 divided by its sum of digits (49) gives a square (1404525529 = 37477²).

The spelling of 68821750921 in words is "sixty-eight billion, eight hundred twenty-one million, seven hundred fifty thousand, nine hundred twenty-one".