687025981 has 8 divisors (see below), whose sum is σ = 739365624. Its totient is φ = 636011520.

The previous prime is 687025961. The next prime is 687026003. The reversal of 687025981 is 189520786.

It can be written as a sum of positive squares in 4 ways, for example, as 13623481 + 673402500 = 3691^2 + 25950^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 687025981 - 2⁷ = 687025853 is a prime.

It is a super-2 number, since 2×687025981² = 944009397138024722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687025901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 330220 + ... + 332293.

It is an arithmetic number, because the mean of its divisors is an integer number (92420703).

Almost surely, 2^687025981 is an apocalyptic number.

687025981 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

687025981 is a deficient number, since it is larger than the sum of its proper divisors (52339643).

687025981 is a wasteful number, since it uses less digits than its factorization.

687025981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662591.

The product of its (nonzero) digits is 241920, while the sum is 46.

The square root of 687025981 is about 26211.1804579649. The cubic root of 687025981 is about 882.3841945054.

The spelling of 687025981 in words is "six hundred eighty-seven million, twenty-five thousand, nine hundred eighty-one".