21906147 has 8 divisors (see below), whose sum is σ = 29578240. Its totient is φ = 14419080.

The previous prime is 21906113. The next prime is 21906151. The reversal of 21906147 is 74160912.

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 21906147 - 2⁶ = 21906083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21906167) 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, 45979 + ... + 46452.

It is an arithmetic number, because the mean of its divisors is an integer number (3697280).

Almost surely, 2^21906147 is an apocalyptic number.

21906147 is a deficient number, since it is larger than the sum of its proper divisors (7672093).

21906147 is an equidigital number, since it uses as much as digits as its factorization.

21906147 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92513.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 21906147 is about 4680.4003033929. The cubic root of 21906147 is about 279.8049108725.

The spelling of 21906147 in words is "twenty-one million, nine hundred six thousand, one hundred forty-seven".