21451976 has 64 divisors (see below), whose sum is σ = 50265600. Its totient is φ = 8356608.

The previous prime is 21451973. The next prime is 21451981. The reversal of 21451976 is 67915412.

It is not an unprimeable number, because it can be changed into a prime (21451973) 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 15 ways as a sum of consecutive naturals, for example, 57326 + ... + 57698.

It is an arithmetic number, because the mean of its divisors is an integer number (785400).

Almost surely, 2^21451976 is an apocalyptic number.

21451976 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21451976, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25132800).

21451976 is an abundant number, since it is smaller than the sum of its proper divisors (28813624).

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

21451976 is a wasteful number, since it uses less digits than its factorization.

21451976 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 478 (or 474 counting only the distinct ones).

The product of its digits is 15120, while the sum is 35.

The square root of 21451976 is about 4631.6277916085. The cubic root of 21451976 is about 277.8576985086.

The spelling of 21451976 in words is "twenty-one million, four hundred fifty-one thousand, nine hundred seventy-six".