21071487 has 8 divisors (see below), whose sum is σ = 29064240. Its totient is φ = 13563200.

The previous prime is 21071467. The next prime is 21071489. The reversal of 21071487 is 78417012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21071487 - 2⁶ = 21071423 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21071489) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 121014 + ... + 121187.

It is an arithmetic number, because the mean of its divisors is an integer number (3633030).

Almost surely, 2^21071487 is an apocalyptic number.

21071487 is a deficient number, since it is larger than the sum of its proper divisors (7992753).

21071487 is a wasteful number, since it uses less digits than its factorization.

21071487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242233.

The product of its (nonzero) digits is 3136, while the sum is 30.

The square root of 21071487 is about 4590.3689394209. The cubic root of 21071487 is about 276.2051221434.

Adding to 21071487 its reverse (78417012), we get a palindrome (99488499).

The spelling of 21071487 in words is "twenty-one million, seventy-one thousand, four hundred eighty-seven".