21755129 has 8 divisors (see below), whose sum is σ = 24135840. Its totient is φ = 19441600.

The previous prime is 21755113. The next prime is 21755137. The reversal of 21755129 is 92155712.

It is a happy number.

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 21755129 - 2⁴ = 21755113 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21755095 and 21755104.

It is not an unprimeable number, because it can be changed into a prime (21755159) 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, 16112 + ... + 17409.

It is an arithmetic number, because the mean of its divisors is an integer number (3016980).

Almost surely, 2^21755129 is an apocalyptic number.

It is an amenable number.

21755129 is a deficient number, since it is larger than the sum of its proper divisors (2380711).

21755129 is a wasteful number, since it uses less digits than its factorization.

21755129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33591.

The product of its digits is 6300, while the sum is 32.

The square root of 21755129 is about 4664.2393806493. The cubic root of 21755129 is about 279.1604486425.

The spelling of 21755129 in words is "twenty-one million, seven hundred fifty-five thousand, one hundred twenty-nine".