21887423 has 2 divisors, whose sum is σ = 21887424. Its totient is φ = 21887422.

The previous prime is 21887419. The next prime is 21887429. The reversal of 21887423 is 32478812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21887423 - 2² = 21887419 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21887429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10943711 + 10943712.

It is an arithmetic number, because the mean of its divisors is an integer number (10943712).

Almost surely, 2^21887423 is an apocalyptic number.

21887423 is a deficient number, since it is larger than the sum of its proper divisors (1).

21887423 is an equidigital number, since it uses as much as digits as its factorization.

21887423 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21504, while the sum is 35.

The square root of 21887423 is about 4678.3996195280. The cubic root of 21887423 is about 279.7251682545.

The spelling of 21887423 in words is "twenty-one million, eight hundred eighty-seven thousand, four hundred twenty-three".