21386047 has 2 divisors, whose sum is σ = 21386048. Its totient is φ = 21386046.

The previous prime is 21385999. The next prime is 21386117. The reversal of 21386047 is 74068312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21386047 - 2¹⁵ = 21353279 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21386147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10693023 + 10693024.

It is an arithmetic number, because the mean of its divisors is an integer number (10693024).

Almost surely, 2^21386047 is an apocalyptic number.

21386047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21386047 is an equidigital number, since it uses as much as digits as its factorization.

21386047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 21386047 is about 4624.5050545977. The cubic root of 21386047 is about 277.5727569417.

The spelling of 21386047 in words is "twenty-one million, three hundred eighty-six thousand, forty-seven".