21070464 has 64 divisors (see below), whose sum is σ = 57519840. Its totient is φ = 6829056.

The previous prime is 21070447. The next prime is 21070477. The reversal of 21070464 is 46407012.

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 (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, 13467 + ... + 14949.

Almost surely, 2^21070464 is an apocalyptic number.

21070464 is a gapful number since it is divisible by the number (24) 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 21070464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28759920).

21070464 is an abundant number, since it is smaller than the sum of its proper divisors (36449376).

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

21070464 is a wasteful number, since it uses less digits than its factorization.

21070464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1537 (or 1525 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 21070464 is about 4590.2575091165. The cubic root of 21070464 is about 276.2006522419.

Adding to 21070464 its reverse (46407012), we get a palindrome (67477476).

The spelling of 21070464 in words is "twenty-one million, seventy thousand, four hundred sixty-four".