21479869 has 16 divisors (see below), whose sum is σ = 23220736. Its totient is φ = 19828800.

The previous prime is 21479851. The next prime is 21479873. The reversal of 21479869 is 96897412.

It is a cyclic number.

It is not a de Polignac number, because 21479869 - 2¹³ = 21471677 is a prime.

It is a super-2 number, since 2×21479869² = 922769544514322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21479839) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 69814 + ... + 70120.

It is an arithmetic number, because the mean of its divisors is an integer number (1451296).

Almost surely, 2^21479869 is an apocalyptic number.

It is an amenable number.

21479869 is a deficient number, since it is larger than the sum of its proper divisors (1740867).

21479869 is a wasteful number, since it uses less digits than its factorization.

21479869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 436.

The product of its digits is 217728, while the sum is 46.

The square root of 21479869 is about 4634.6379578129. The cubic root of 21479869 is about 277.9780748024.

The spelling of 21479869 in words is "twenty-one million, four hundred seventy-nine thousand, eight hundred sixty-nine".