21231929 has 8 divisors (see below), whose sum is σ = 22735080. Its totient is φ = 19757056.

The previous prime is 21231923. The next prime is 21231937. The reversal of 21231929 is 92913212.

It can be written as a sum of positive squares in 4 ways, for example, as 511225 + 20720704 = 715^2 + 4552^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21231929 - 2²⁰ = 20183353 is a prime.

It is a super-2 number, since 2×21231929² = 901589618122082, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21231923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5504 + ... + 8529.

It is an arithmetic number, because the mean of its divisors is an integer number (2841885).

Almost surely, 2^21231929 is an apocalyptic number.

It is an amenable number.

21231929 is a deficient number, since it is larger than the sum of its proper divisors (1503151).

21231929 is a wasteful number, since it uses less digits than its factorization.

21231929 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14139.

The product of its digits is 1944, while the sum is 29.

The square root of 21231929 is about 4607.8117366056. The cubic root of 21231929 is about 276.9043751477.

The spelling of 21231929 in words is "twenty-one million, two hundred thirty-one thousand, nine hundred twenty-nine".