21254819 has 2 divisors, whose sum is σ = 21254820. Its totient is φ = 21254818.

The previous prime is 21254813. The next prime is 21254839. The reversal of 21254819 is 91845212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21254819 - 2¹⁶ = 21189283 is a prime.

It is a super-2 number, since 2×21254819² = 903534661445522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21254813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10627409 + 10627410.

It is an arithmetic number, because the mean of its divisors is an integer number (10627410).

Almost surely, 2^21254819 is an apocalyptic number.

21254819 is a deficient number, since it is larger than the sum of its proper divisors (1).

21254819 is an equidigital number, since it uses as much as digits as its factorization.

21254819 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5760, while the sum is 32.

The square root of 21254819 is about 4610.2948929542. The cubic root of 21254819 is about 277.0038489910.

The spelling of 21254819 in words is "twenty-one million, two hundred fifty-four thousand, eight hundred nineteen".