681742051 has 2 divisors, whose sum is σ = 681742052. Its totient is φ = 681742050.

The previous prime is 681742037. The next prime is 681742067. The reversal of 681742051 is 150247186.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 681742051 - 2¹⁵ = 681709283 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 681741998 and 681742016.

It is not a weakly prime, because it can be changed into another prime (681742001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340871025 + 340871026.

It is an arithmetic number, because the mean of its divisors is an integer number (340871026).

Almost surely, 2^681742051 is an apocalyptic number.

681742051 is a deficient number, since it is larger than the sum of its proper divisors (1).

681742051 is an equidigital number, since it uses as much as digits as its factorization.

681742051 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13440, while the sum is 34.

The square root of 681742051 is about 26110.1905584774. The cubic root of 681742051 is about 880.1162256096.

It can be divided in two parts, 68174 and 2051, that added together give a square (70225 = 265²).

The spelling of 681742051 in words is "six hundred eighty-one million, seven hundred forty-two thousand, fifty-one".