21463040 has 64 divisors (see below), whose sum is σ = 51903720. Its totient is φ = 8519680.

The previous prime is 21463031. The next prime is 21463051. The reversal of 21463040 is 4036412.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 163775 + ... + 163905.

Almost surely, 2^21463040 is an apocalyptic number.

21463040 is a gapful number since it is divisible by the number (20) 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 21463040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25951860).

21463040 is an abundant number, since it is smaller than the sum of its proper divisors (30440680).

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

21463040 is an frugal number, since it uses more digits than its factorization.

21463040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166 (or 138 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 21463040 is about 4632.8220341386. The cubic root of 21463040 is about 277.9054592869.

Adding to 21463040 its reverse (4036412), we get a palindrome (25499452).

The spelling of 21463040 in words is "twenty-one million, four hundred sixty-three thousand, forty".