21072150 has 180 divisors, whose sum is σ = 65852556. Its totient is φ = 4989600.

The previous prime is 21072137. The next prime is 21072169. The reversal of 21072150 is 5127012.

21072150 = 165² + 166² + ... + 407².

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 89 ways as a sum of consecutive naturals, for example, 490029 + ... + 490071.

Almost surely, 2^21072150 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21072150, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32926278).

21072150 is an abundant number, since it is smaller than the sum of its proper divisors (44780406).

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

21072150 is a wasteful number, since it uses less digits than its factorization.

21072150 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89 (or 64 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 18.

The square root of 21072150 is about 4590.4411552704. The cubic root of 21072150 is about 276.2080189818.

Adding to 21072150 its reverse (5127012), we get a palindrome (26199162).

The spelling of 21072150 in words is "twenty-one million, seventy-two thousand, one hundred fifty".