21152730 has 32 divisors (see below), whose sum is σ = 51004800. Its totient is φ = 5614272.

The previous prime is 21152713. The next prime is 21152731. The reversal of 21152730 is 3725112.

It is a junction number, because it is equal to n+sod(n) for n = 21152697 and 21152706.

It is not an unprimeable number, because it can be changed into a prime (21152731) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5331 + ... + 8409.

It is an arithmetic number, because the mean of its divisors is an integer number (1593900).

Almost surely, 2^21152730 is an apocalyptic number.

21152730 is an abundant number, since it is smaller than the sum of its proper divisors (29852070).

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

21152730 is a wasteful number, since it uses less digits than its factorization.

21152730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3318.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 21152730 is about 4599.2097147227. The cubic root of 21152730 is about 276.5596447405.

Adding to 21152730 its reverse (3725112), we get a palindrome (24877842).

The spelling of 21152730 in words is "twenty-one million, one hundred fifty-two thousand, seven hundred thirty".