21152406 has 32 divisors (see below), whose sum is σ = 47029248. Its totient is φ = 6287840.

The previous prime is 21152399. The next prime is 21152413. The reversal of 21152406 is 60425112.

It is an interprime number because it is at equal distance from previous prime (21152399) and next prime (21152413).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 475 + ... + 6521.

It is an arithmetic number, because the mean of its divisors is an integer number (1469664).

Almost surely, 2^21152406 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21152406, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23514624).

21152406 is an abundant number, since it is smaller than the sum of its proper divisors (25876842).

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

21152406 is a wasteful number, since it uses less digits than its factorization.

21152406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6116.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 21152406 is about 4599.1744911451. The cubic root of 21152406 is about 276.5582326961.

Adding to 21152406 its reverse (60425112), we get a palindrome (81577518).

The spelling of 21152406 in words is "twenty-one million, one hundred fifty-two thousand, four hundred six".