67720531 has 2 divisors, whose sum is σ = 67720532. Its totient is φ = 67720530.

The previous prime is 67720507. The next prime is 67720547. The reversal of 67720531 is 13502776.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 67720531 - 2⁷ = 67720403 is a prime.

It is a super-2 number, since 2×67720531² = 9172140637843922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 67720493 and 67720502.

It is not a weakly prime, because it can be changed into another prime (67720831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33860265 + 33860266.

It is an arithmetic number, because the mean of its divisors is an integer number (33860266).

Almost surely, 2^67720531 is an apocalyptic number.

67720531 is a deficient number, since it is larger than the sum of its proper divisors (1).

67720531 is an equidigital number, since it uses as much as digits as its factorization.

67720531 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8820, while the sum is 31.

The square root of 67720531 is about 8229.2485076099. The cubic root of 67720531 is about 407.6055776723.

The spelling of 67720531 in words is "sixty-seven million, seven hundred twenty thousand, five hundred thirty-one".