21070929 has 16 divisors (see below), whose sum is σ = 30818304. Its totient is φ = 12699600.

The previous prime is 21070919. The next prime is 21070937. The reversal of 21070929 is 92907012.

It is not a de Polignac number, because 21070929 - 2⁴ = 21070913 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21070896 and 21070905.

It is not an unprimeable number, because it can be changed into a prime (21070909) 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, 4632 + ... + 7974.

It is an arithmetic number, because the mean of its divisors is an integer number (1926144).

Almost surely, 2^21070929 is an apocalyptic number.

It is an amenable number.

21070929 is a deficient number, since it is larger than the sum of its proper divisors (9747375).

21070929 is a wasteful number, since it uses less digits than its factorization.

21070929 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3548.

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

The square root of 21070929 is about 4590.3081595902. The cubic root of 21070929 is about 276.2026840333.

The spelling of 21070929 in words is "twenty-one million, seventy thousand, nine hundred twenty-nine".