681248621 has 4 divisors (see below), whose sum is σ = 690843744. Its totient is φ = 671653500.

The previous prime is 681248593. The next prime is 681248639. The reversal of 681248621 is 126842186.

It is a happy number.

681248621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 126842186 = 2 ⋅63421093.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681248621 is a prime.

It is a super-2 number, since 2×681248621² = 928199367228803282, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681247621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4797455 + ... + 4797596.

It is an arithmetic number, because the mean of its divisors is an integer number (172710936).

Almost surely, 2^681248621 is an apocalyptic number.

It is an amenable number.

681248621 is a deficient number, since it is larger than the sum of its proper divisors (9595123).

681248621 is an equidigital number, since it uses as much as digits as its factorization.

681248621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9595122.

The product of its digits is 36864, while the sum is 38.

The square root of 681248621 is about 26100.7398554141. The cubic root of 681248621 is about 879.9038380632.

The spelling of 681248621 in words is "six hundred eighty-one million, two hundred forty-eight thousand, six hundred twenty-one".