67680781 has 16 divisors (see below), whose sum is σ = 81169408. Its totient is φ = 55209600.

The previous prime is 67680779. The next prime is 67680797. The reversal of 67680781 is 18708676.

67680781 = 158² + 159² + ... + 591².

It is a cyclic number.

It is not a de Polignac number, because 67680781 - 2¹ = 67680779 is a prime.

It is a super-2 number, since 2×67680781² = 9161376233539922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (67689781) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10681 + ... + 15793.

It is an arithmetic number, because the mean of its divisors is an integer number (5073088).

Almost surely, 2^67680781 is an apocalyptic number.

67680781 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

67680781 is a deficient number, since it is larger than the sum of its proper divisors (13488627).

67680781 is a wasteful number, since it uses less digits than its factorization.

67680781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5212.

The product of its (nonzero) digits is 112896, while the sum is 43.

The square root of 67680781 is about 8226.8329872436. The cubic root of 67680781 is about 407.5258111544.

The spelling of 67680781 in words is "sixty-seven million, six hundred eighty thousand, seven hundred eighty-one".