681889951 has 2 divisors, whose sum is σ = 681889952. Its totient is φ = 681889950.

The previous prime is 681889933. The next prime is 681889961. The reversal of 681889951 is 159988186.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 681889951 - 2¹⁷ = 681758879 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 681889892 and 681889901.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681889931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340944975 + 340944976.

It is an arithmetic number, because the mean of its divisors is an integer number (340944976).

Almost surely, 2^681889951 is an apocalyptic number.

681889951 is a deficient number, since it is larger than the sum of its proper divisors (1).

681889951 is an equidigital number, since it uses as much as digits as its factorization.

681889951 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1244160, while the sum is 55.

The square root of 681889951 is about 26113.0226323955. The cubic root of 681889951 is about 880.1798663848.

It can be divided in two parts, 6818 and 89951, that added together give a palindrome (96769).

The spelling of 681889951 in words is "six hundred eighty-one million, eight hundred eighty-nine thousand, nine hundred fifty-one".