21169091 has 2 divisors, whose sum is σ = 21169092. Its totient is φ = 21169090.

The previous prime is 21169073. The next prime is 21169121. The reversal of 21169091 is 19096112.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21169091 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21169061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10584545 + 10584546.

It is an arithmetic number, because the mean of its divisors is an integer number (10584546).

Almost surely, 2^21169091 is an apocalyptic number.

21169091 is a deficient number, since it is larger than the sum of its proper divisors (1).

21169091 is an equidigital number, since it uses as much as digits as its factorization.

21169091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972, while the sum is 29.

The square root of 21169091 is about 4600.9880460614. The cubic root of 21169091 is about 276.6309298852.

The spelling of 21169091 in words is "twenty-one million, one hundred sixty-nine thousand, ninety-one".