21071960 has 96 divisors (see below), whose sum is σ = 59466960. Its totient is φ = 6660864.

The previous prime is 21071927. The next prime is 21071977. The reversal of 21071960 is 6917012.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25067 + ... + 25893.

Almost surely, 2^21071960 is an apocalyptic number.

21071960 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 21071960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29733480).

21071960 is an abundant number, since it is smaller than the sum of its proper divisors (38395000).

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

21071960 is a wasteful number, since it uses less digits than its factorization.

21071960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 865 (or 854 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 26.

The square root of 21071960 is about 4590.4204600450. The cubic root of 21071960 is about 276.2071888232.

Adding to 21071960 its reverse (6917012), we get a palindrome (27988972).

The spelling of 21071960 in words is "twenty-one million, seventy-one thousand, nine hundred sixty".