21700929 has 16 divisors (see below), whose sum is σ = 29538432. Its totient is φ = 14168448.

The previous prime is 21700901. The next prime is 21700949. The reversal of 21700929 is 92900712.

It is not a de Polignac number, because 21700929 - 2⁸ = 21700673 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21700896 and 21700905.

It is not an unprimeable number, because it can be changed into a prime (21700949) 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, 42892 + ... + 43394.

It is an arithmetic number, because the mean of its divisors is an integer number (1846152).

Almost surely, 2^21700929 is an apocalyptic number.

It is an amenable number.

21700929 is a deficient number, since it is larger than the sum of its proper divisors (7837503).

21700929 is a wasteful number, since it uses less digits than its factorization.

21700929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 776.

The product of its (nonzero) digits is 2268, while the sum is 30.

The square root of 21700929 is about 4658.4255924078. The cubic root of 21700929 is about 278.9284255191.

The spelling of 21700929 in words is "twenty-one million, seven hundred thousand, nine hundred twenty-nine".