21129606 has 32 divisors (see below), whose sum is σ = 49718880. Its totient is φ = 6628608.

The previous prime is 21129587. The next prime is 21129613. The reversal of 21129606 is 60692112.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 21129606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10591 + ... + 12426.

It is an arithmetic number, because the mean of its divisors is an integer number (1553715).

Almost surely, 2^21129606 is an apocalyptic number.

21129606 is an abundant number, since it is smaller than the sum of its proper divisors (28589274).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21129606 is a wasteful number, since it uses less digits than its factorization.

21129606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23045 (or 23039 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 21129606 is about 4596.6951171467. The cubic root of 21129606 is about 276.4588303772.

The spelling of 21129606 in words is "twenty-one million, one hundred twenty-nine thousand, six hundred six".