21387463 has 2 divisors, whose sum is σ = 21387464. Its totient is φ = 21387462.

The previous prime is 21387451. The next prime is 21387473. The reversal of 21387463 is 36478312.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21387463 - 2¹³ = 21379271 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21387403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10693731 + 10693732.

It is an arithmetic number, because the mean of its divisors is an integer number (10693732).

Almost surely, 2^21387463 is an apocalyptic number.

21387463 is a deficient number, since it is larger than the sum of its proper divisors (1).

21387463 is an equidigital number, since it uses as much as digits as its factorization.

21387463 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24192, while the sum is 34.

The square root of 21387463 is about 4624.6581495285. The cubic root of 21387463 is about 277.5788829662.

The spelling of 21387463 in words is "twenty-one million, three hundred eighty-seven thousand, four hundred sixty-three".