21201487 has 2 divisors, whose sum is σ = 21201488. Its totient is φ = 21201486.

The previous prime is 21201461. The next prime is 21201497. The reversal of 21201487 is 78410212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21201487 is a prime.

It is a super-2 number, since 2×21201487² = 899006102022338, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600743 + 10600744.

It is an arithmetic number, because the mean of its divisors is an integer number (10600744).

Almost surely, 2^21201487 is an apocalyptic number.

21201487 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201487 is an equidigital number, since it uses as much as digits as its factorization.

21201487 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 21201487 is about 4604.5072483383. The cubic root of 21201487 is about 276.7719714943.

Adding to 21201487 its reverse (78410212), we get a palindrome (99611699).

The spelling of 21201487 in words is "twenty-one million, two hundred one thousand, four hundred eighty-seven".