681440290 has 8 divisors (see below), whose sum is σ = 1226592540. Its totient is φ = 272576112.

The previous prime is 681440269. The next prime is 681440293. The reversal of 681440290 is 92044186.

It can be written as a sum of positive squares in 2 ways, for example, as 667653921 + 13786369 = 25839^2 + 3713^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (681440293) 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, 34072005 + ... + 34072024.

Almost surely, 2^681440290 is an apocalyptic number.

681440290 is a deficient number, since it is larger than the sum of its proper divisors (545152250).

681440290 is a wasteful number, since it uses less digits than its factorization.

681440290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68144036.

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 681440290 is about 26104.4113130329. The cubic root of 681440290 is about 879.9863505114.

The spelling of 681440290 in words is "six hundred eighty-one million, four hundred forty thousand, two hundred ninety".