21712423 has 2 divisors, whose sum is σ = 21712424. Its totient is φ = 21712422.

The previous prime is 21712393. The next prime is 21712469. The reversal of 21712423 is 32421712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21712423 - 2¹³ = 21704231 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21712394 and 21712403.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21722423) 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, 10856211 + 10856212.

It is an arithmetic number, because the mean of its divisors is an integer number (10856212).

Almost surely, 2^21712423 is an apocalyptic number.

21712423 is a deficient number, since it is larger than the sum of its proper divisors (1).

21712423 is an equidigital number, since it uses as much as digits as its factorization.

21712423 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 672, while the sum is 22.

The square root of 21712423 is about 4659.6591077031. The cubic root of 21712423 is about 278.9776620819.

The spelling of 21712423 in words is "twenty-one million, seven hundred twelve thousand, four hundred twenty-three".