21061747 has 8 divisors (see below), whose sum is σ = 25337600. Its totient is φ = 17102664.

The previous prime is 21061739. The next prime is 21061757. The reversal of 21061747 is 74716012.

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 21061747 - 2³ = 21061739 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21061717) 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, 79047 + ... + 79312.

It is an arithmetic number, because the mean of its divisors is an integer number (3167200).

Almost surely, 2^21061747 is an apocalyptic number.

21061747 is a deficient number, since it is larger than the sum of its proper divisors (4275853).

21061747 is a wasteful number, since it uses less digits than its factorization.

21061747 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158385.

The product of its (nonzero) digits is 2352, while the sum is 28.

The square root of 21061747 is about 4589.3078998908. The cubic root of 21061747 is about 276.1625582670.

Adding to 21061747 its reverse (74716012), we get a palindrome (95777759).

The spelling of 21061747 in words is "twenty-one million, sixty-one thousand, seven hundred forty-seven".