21047562 has 48 divisors (see below), whose sum is σ = 48021480. Its totient is φ = 6652800.

The previous prime is 21047539. The next prime is 21047563. The reversal of 21047562 is 26574012.

It can be written as a sum of positive squares in 4 ways, for example, as 15752961 + 5294601 = 3969^2 + 2301^2 .

It is a super-2 number, since 2×21047562² = 885999732287688, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21047563) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 31512 + ... + 32172.

Almost surely, 2^21047562 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21047562, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24010740).

21047562 is an abundant number, since it is smaller than the sum of its proper divisors (26973918).

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

21047562 is a wasteful number, since it uses less digits than its factorization.

21047562 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 759 (or 756 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 21047562 is about 4587.7621995914. The cubic root of 21047562 is about 276.1005462275.

It can be divided in two parts, 21047 and 562, that added together give a square (21609 = 147²).

The spelling of 21047562 in words is "twenty-one million, forty-seven thousand, five hundred sixty-two".