681421645 has 16 divisors (see below), whose sum is σ = 838518912. Its totient is φ = 531316800.

The previous prime is 681421619. The next prime is 681421673. The reversal of 681421645 is 546124186.

It is not a de Polignac number, because 681421645 - 2⁹ = 681421133 is a prime.

It is a super-3 number, since 3×681421645³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 104995 + ... + 111295.

It is an arithmetic number, because the mean of its divisors is an integer number (52407432).

Almost surely, 2^681421645 is an apocalyptic number.

It is an amenable number.

681421645 is a deficient number, since it is larger than the sum of its proper divisors (157097267).

681421645 is a wasteful number, since it uses less digits than its factorization.

681421645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6852.

The product of its digits is 46080, while the sum is 37.

The square root of 681421645 is about 26104.0541870415. The cubic root of 681421645 is about 879.9783246211.

The spelling of 681421645 in words is "six hundred eighty-one million, four hundred twenty-one thousand, six hundred forty-five".