21478867 has 2 divisors, whose sum is σ = 21478868. Its totient is φ = 21478866.

The previous prime is 21478861. The next prime is 21478883. The reversal of 21478867 is 76887412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21478867 - 2⁷ = 21478739 is a prime.

It is a super-2 number, since 2×21478867² = 922683455207378, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21478861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10739433 + 10739434.

It is an arithmetic number, because the mean of its divisors is an integer number (10739434).

Almost surely, 2^21478867 is an apocalyptic number.

21478867 is a deficient number, since it is larger than the sum of its proper divisors (1).

21478867 is an equidigital number, since it uses as much as digits as its factorization.

21478867 is an evil number, because the sum of its binary digits is even.

The product of its digits is 150528, while the sum is 43.

The square root of 21478867 is about 4634.5298574936. The cubic root of 21478867 is about 277.9737523310.

The spelling of 21478867 in words is "twenty-one million, four hundred seventy-eight thousand, eight hundred sixty-seven".