21007460 has 36 divisors (see below), whose sum is σ = 45626364. Its totient is φ = 8124480.

The previous prime is 21007439. The next prime is 21007463. The reversal of 21007460 is 6470012.

It can be written as a sum of positive squares in 2 ways, for example, as 15745024 + 5262436 = 3968^2 + 2294^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21007463) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18674 + ... + 19766.

It is an arithmetic number, because the mean of its divisors is an integer number (1267399).

Almost surely, 2^21007460 is an apocalyptic number.

21007460 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 21007460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22813182).

21007460 is an abundant number, since it is smaller than the sum of its proper divisors (24618904).

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

21007460 is a wasteful number, since it uses less digits than its factorization.

21007460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1164 (or 1131 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 21007460 is about 4583.3895754125. The cubic root of 21007460 is about 275.9250829361.

Adding to 21007460 its reverse (6470012), we get a palindrome (27477472).

The spelling of 21007460 in words is "twenty-one million, seven thousand, four hundred sixty".