21651080 has 32 divisors (see below), whose sum is σ = 53144640. Its totient is φ = 7872960.

The previous prime is 21651043. The next prime is 21651101. The reversal of 21651080 is 8015612.

It is an unprimeable number.

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, 24164 + ... + 25043.

It is an arithmetic number, because the mean of its divisors is an integer number (1660770).

Almost surely, 2^21651080 is an apocalyptic number.

21651080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21651080 is an abundant number, since it is smaller than the sum of its proper divisors (31493560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21651080 is a wasteful number, since it uses less digits than its factorization.

21651080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49229 (or 49225 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 21651080 is about 4653.0721034603. The cubic root of 21651080 is about 278.7146871553.

Adding to 21651080 its reverse (8015612), we get a palindrome (29666692).

The spelling of 21651080 in words is "twenty-one million, six hundred fifty-one thousand, eighty".