21690707 has 2 divisors, whose sum is σ = 21690708. Its totient is φ = 21690706.

The previous prime is 21690703. The next prime is 21690733. The reversal of 21690707 is 70709612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21690707 - 2² = 21690703 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (21690703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10845353 + 10845354.

It is an arithmetic number, because the mean of its divisors is an integer number (10845354).

Almost surely, 2^21690707 is an apocalyptic number.

21690707 is a deficient number, since it is larger than the sum of its proper divisors (1).

21690707 is an equidigital number, since it uses as much as digits as its factorization.

21690707 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5292, while the sum is 32.

The square root of 21690707 is about 4657.3283113820. The cubic root of 21690707 is about 278.8846231829.

The spelling of 21690707 in words is "twenty-one million, six hundred ninety thousand, seven hundred seven".