21641064 has 32 divisors (see below), whose sum is σ = 54397440. Its totient is φ = 7174400.

The previous prime is 21641027. The next prime is 21641093. The reversal of 21641064 is 46014612.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2224 + ... + 6944.

It is an arithmetic number, because the mean of its divisors is an integer number (1699920).

Almost surely, 2^21641064 is an apocalyptic number.

21641064 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21641064 is an abundant number, since it is smaller than the sum of its proper divisors (32756376).

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

21641064 is a wasteful number, since it uses less digits than its factorization.

21641064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4921 (or 4917 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 21641064 is about 4651.9957007719. The cubic root of 21641064 is about 278.6717018186.

Adding to 21641064 its reverse (46014612), we get a palindrome (67655676).

The spelling of 21641064 in words is "twenty-one million, six hundred forty-one thousand, sixty-four".