21654019 has 2 divisors, whose sum is σ = 21654020. Its totient is φ = 21654018.

The previous prime is 21654013. The next prime is 21654029. The reversal of 21654019 is 91045612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21654019 - 2⁵ = 21653987 is a prime.

It is a super-2 number, since 2×21654019² = 937793077704722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21654013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10827009 + 10827010.

It is an arithmetic number, because the mean of its divisors is an integer number (10827010).

Almost surely, 2^21654019 is an apocalyptic number.

21654019 is a deficient number, since it is larger than the sum of its proper divisors (1).

21654019 is an equidigital number, since it uses as much as digits as its factorization.

21654019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 21654019 is about 4653.3879056017. The cubic root of 21654019 is about 278.7272978488.

The spelling of 21654019 in words is "twenty-one million, six hundred fifty-four thousand, nineteen".