21229755 has 8 divisors (see below), whose sum is σ = 33967632. Its totient is φ = 11322528.

The previous prime is 21229751. The next prime is 21229757. The reversal of 21229755 is 55792212.

It is a happy number.

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

It is not a de Polignac number, because 21229755 - 2² = 21229751 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21229751) 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, 707644 + ... + 707673.

It is an arithmetic number, because the mean of its divisors is an integer number (4245954).

Almost surely, 2^21229755 is an apocalyptic number.

21229755 is a deficient number, since it is larger than the sum of its proper divisors (12737877).

21229755 is a wasteful number, since it uses less digits than its factorization.

21229755 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1415325.

The product of its digits is 12600, while the sum is 33.

The square root of 21229755 is about 4607.5758268313. The cubic root of 21229755 is about 276.8949238058.

The spelling of 21229755 in words is "twenty-one million, two hundred twenty-nine thousand, seven hundred fifty-five".