21742929 has 24 divisors (see below), whose sum is σ = 34245120. Its totient is φ = 13213152.

The previous prime is 21742913. The next prime is 21742961. The reversal of 21742929 is 92924712.

It is not a de Polignac number, because 21742929 - 2⁴ = 21742913 is a prime.

It is a super-2 number, since 2×21742929² = 945509922998082, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21742893 and 21742902.

It is not an unprimeable number, because it can be changed into a prime (21742829) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8592 + ... + 10830.

It is an arithmetic number, because the mean of its divisors is an integer number (1426880).

Almost surely, 2^21742929 is an apocalyptic number.

It is an amenable number.

21742929 is a deficient number, since it is larger than the sum of its proper divisors (12502191).

21742929 is a wasteful number, since it uses less digits than its factorization.

21742929 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2341 (or 2338 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 21742929 is about 4662.9313741465. The cubic root of 21742929 is about 279.1082556737.

The spelling of 21742929 in words is "twenty-one million, seven hundred forty-two thousand, nine hundred twenty-nine".