20689967 has 2 divisors, whose sum is σ = 20689968. Its totient is φ = 20689966.

The previous prime is 20689913. The next prime is 20689973. The reversal of 20689967 is 76998602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20689967 - 2¹² = 20685871 is a prime.

It is a super-2 number, since 2×20689967² = 856149468922178, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20689987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10344983 + 10344984.

It is an arithmetic number, because the mean of its divisors is an integer number (10344984).

Almost surely, 2^20689967 is an apocalyptic number.

20689967 is a deficient number, since it is larger than the sum of its proper divisors (1).

20689967 is an equidigital number, since it uses as much as digits as its factorization.

20689967 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 326592, while the sum is 47.

The square root of 20689967 is about 4548.6225387473. The cubic root of 20689967 is about 274.5279704036.

The spelling of 20689967 in words is "twenty million, six hundred eighty-nine thousand, nine hundred sixty-seven".