21526487 has 8 divisors (see below), whose sum is σ = 22738560. Its totient is φ = 20322360.

The previous prime is 21526469. The next prime is 21526499. The reversal of 21526487 is 78462512.

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 21526487 - 2¹⁰ = 21525463 is a prime.

It is a super-2 number, since 2×21526487² = 926779285122338, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21526447) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4088 + ... + 7730.

It is an arithmetic number, because the mean of its divisors is an integer number (2842320).

Almost surely, 2^21526487 is an apocalyptic number.

21526487 is a deficient number, since it is larger than the sum of its proper divisors (1212073).

21526487 is a wasteful number, since it uses less digits than its factorization.

21526487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3973.

The product of its digits is 26880, while the sum is 35.

The square root of 21526487 is about 4639.6645352870. The cubic root of 21526487 is about 278.1790291366.

Adding to 21526487 its reverse (78462512), we get a palindrome (99988999).

The spelling of 21526487 in words is "twenty-one million, five hundred twenty-six thousand, four hundred eighty-seven".