21661627 has 4 divisors (see below), whose sum is σ = 23327920. Its totient is φ = 19995336.

The previous prime is 21661609. The next prime is 21661639. The reversal of 21661627 is 72616612.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21661627 - 2⁷ = 21661499 is a prime.

It is a Duffinian number.

It is a plaindrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (21661657) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 833127 + ... + 833152.

It is an arithmetic number, because the mean of its divisors is an integer number (5831980).

Almost surely, 2^21661627 is an apocalyptic number.

21661627 is a deficient number, since it is larger than the sum of its proper divisors (1666293).

21661627 is a wasteful number, since it uses less digits than its factorization.

21661627 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1666292.

The product of its digits is 6048, while the sum is 31.

The square root of 21661627 is about 4654.2053027343. The cubic root of 21661627 is about 278.7599370398.

The spelling of 21661627 in words is "twenty-one million, six hundred sixty-one thousand, six hundred twenty-seven".