21478007 has 2 divisors, whose sum is σ = 21478008. Its totient is φ = 21478006.

The previous prime is 21477991. The next prime is 21478049. The reversal of 21478007 is 70087412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21478007 - 2⁴ = 21477991 is a prime.

It is a super-2 number, since 2×21478007² = 922609569384098, which contains 22 as substring.

It is equal to p_1358318 and since 21478007 and 1358318 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21478057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10739003 + 10739004.

It is an arithmetic number, because the mean of its divisors is an integer number (10739004).

Almost surely, 2^21478007 is an apocalyptic number.

21478007 is a deficient number, since it is larger than the sum of its proper divisors (1).

21478007 is an equidigital number, since it uses as much as digits as its factorization.

21478007 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3136, while the sum is 29.

The square root of 21478007 is about 4634.4370747697. The cubic root of 21478007 is about 277.9700423181.

The spelling of 21478007 in words is "twenty-one million, four hundred seventy-eight thousand, seven".