681304402 has 4 divisors (see below), whose sum is σ = 1021956606. Its totient is φ = 340652200.

The previous prime is 681304399. The next prime is 681304409. The reversal of 681304402 is 204403186.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 679175721 + 2128681 = 26061^2 + 1459^2 .

It is not an unprimeable number, because it can be changed into a prime (681304409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 170326099 + ... + 170326102.

Almost surely, 2^681304402 is an apocalyptic number.

681304402 is a deficient number, since it is larger than the sum of its proper divisors (340652204).

681304402 is a wasteful number, since it uses less digits than its factorization.

681304402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340652203.

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 681304402 is about 26101.8084047830. The cubic root of 681304402 is about 879.9278530728.

Adding to 681304402 its reverse (204403186), we get a palindrome (885707588).

The spelling of 681304402 in words is "six hundred eighty-one million, three hundred four thousand, four hundred two".