21651010 has 16 divisors (see below), whose sum is σ = 39139200. Its totient is φ = 8623216.

The previous prime is 21650999. The next prime is 21651011. The reversal of 21651010 is 1015612.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21651011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2140 + ... + 6919.

It is an arithmetic number, because the mean of its divisors is an integer number (2446200).

Almost surely, 2^21651010 is an apocalyptic number.

21651010 is a deficient number, since it is larger than the sum of its proper divisors (17488190).

21651010 is a wasteful number, since it uses less digits than its factorization.

21651010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9305.

The product of its (nonzero) digits is 60, while the sum is 16.

The square root of 21651010 is about 4653.0645815419. The cubic root of 21651010 is about 278.7143867846.

Adding to 21651010 its reverse (1015612), we get a palindrome (22666622).

The spelling of 21651010 in words is "twenty-one million, six hundred fifty-one thousand, ten".