21634659 has 12 divisors (see below), whose sum is σ = 33088536. Its totient is φ = 13574592.

The previous prime is 21634649. The next prime is 21634661. The reversal of 21634659 is 95643612.

It is a happy number.

It is not a de Polignac number, because 21634659 - 2¹² = 21630563 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21634649) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 70549 + ... + 70854.

It is an arithmetic number, because the mean of its divisors is an integer number (2757378).

Almost surely, 2^21634659 is an apocalyptic number.

21634659 is a deficient number, since it is larger than the sum of its proper divisors (11453877).

21634659 is a wasteful number, since it uses less digits than its factorization.

21634659 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141426 (or 141423 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 21634659 is about 4651.3072356059. The cubic root of 21634659 is about 278.6442067384.

The spelling of 21634659 in words is "twenty-one million, six hundred thirty-four thousand, six hundred fifty-nine".