21154464 has 36 divisors (see below), whose sum is σ = 60158826. Its totient is φ = 7051392.

The previous prime is 21154447. The next prime is 21154487. The reversal of 21154464 is 46445112.

21154464 is a `hidden beast` number, since 211 + 5 + 446 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 16744464 + 4410000 = 4092^2 + 2100^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×21154464² = 895022694254592, which contains 22 as substring.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36439 + ... + 37014.

Almost surely, 2^21154464 is an apocalyptic number.

21154464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21154464 is an abundant number, since it is smaller than the sum of its proper divisors (39004362).

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

21154464 is a wasteful number, since it uses less digits than its factorization.

21154464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73469 (or 73458 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

The square root of 21154464 is about 4599.3982215068. The cubic root of 21154464 is about 276.5672015480.

Adding to 21154464 its reverse (46445112), we get a palindrome (67599576).

The spelling of 21154464 in words is "twenty-one million, one hundred fifty-four thousand, four hundred sixty-four".