21051662 has 4 divisors (see below), whose sum is σ = 31577496. Its totient is φ = 10525830.

The previous prime is 21051643. The next prime is 21051673. The reversal of 21051662 is 26615012.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5262914 + ... + 5262917.

It is an arithmetic number, because the mean of its divisors is an integer number (7894374).

Almost surely, 2^21051662 is an apocalyptic number.

21051662 is a deficient number, since it is larger than the sum of its proper divisors (10525834).

21051662 is a wasteful number, since it uses less digits than its factorization.

21051662 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10525833.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 21051662 is about 4588.2090187785. The cubic root of 21051662 is about 276.1184729078.

Adding to 21051662 its reverse (26615012), we get a palindrome (47666674).

The spelling of 21051662 in words is "twenty-one million, fifty-one thousand, six hundred sixty-two".