21934691 has 2 divisors, whose sum is σ = 21934692. Its totient is φ = 21934690.

The previous prime is 21934681. The next prime is 21934699. The reversal of 21934691 is 19643912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21934691 - 2¹⁴ = 21918307 is a prime.

It is a super-2 number, since 2×21934691² = 962261338530962, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21934699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10967345 + 10967346.

It is an arithmetic number, because the mean of its divisors is an integer number (10967346).

Almost surely, 2^21934691 is an apocalyptic number.

21934691 is a deficient number, since it is larger than the sum of its proper divisors (1).

21934691 is an equidigital number, since it uses as much as digits as its factorization.

21934691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11664, while the sum is 35.

The square root of 21934691 is about 4683.4486225430. The cubic root of 21934691 is about 279.9263879620.

The spelling of 21934691 in words is "twenty-one million, nine hundred thirty-four thousand, six hundred ninety-one".