21942155 has 8 divisors (see below), whose sum is σ = 27879552. Its totient is φ = 16521088.

The previous prime is 21942143. The next prime is 21942191. The reversal of 21942155 is 55124912.

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 21942155 - 2⁴ = 21942139 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 128987 + ... + 129156.

It is an arithmetic number, because the mean of its divisors is an integer number (3484944).

Almost surely, 2^21942155 is an apocalyptic number.

21942155 is a deficient number, since it is larger than the sum of its proper divisors (5937397).

21942155 is a wasteful number, since it uses less digits than its factorization.

21942155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258165.

The product of its digits is 3600, while the sum is 29.

The square root of 21942155 is about 4684.2454034775. The cubic root of 21942155 is about 279.9581357478.

The spelling of 21942155 in words is "twenty-one million, nine hundred forty-two thousand, one hundred fifty-five".