21472840 has 32 divisors (see below), whose sum is σ = 48600000. Its totient is φ = 8538304.

The previous prime is 21472817. The next prime is 21472849. The reversal of 21472840 is 4827412.

It is a super-2 number, since 2×21472840² = 922165715331200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21472799 and 21472808.

It is not an unprimeable number, because it can be changed into a prime (21472849) 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, 5661 + ... + 8659.

It is an arithmetic number, because the mean of its divisors is an integer number (1518750).

Almost surely, 2^21472840 is an apocalyptic number.

21472840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21472840 is an abundant number, since it is smaller than the sum of its proper divisors (27127160).

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

21472840 is a wasteful number, since it uses less digits than its factorization.

21472840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3189 (or 3185 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 28.

The square root of 21472840 is about 4633.8795841066. The cubic root of 21472840 is about 277.9477499580.

The spelling of 21472840 in words is "twenty-one million, four hundred seventy-two thousand, eight hundred forty".