21957030 has 96 divisors (see below), whose sum is σ = 61461504. Its totient is φ = 5419008.

The previous prime is 21956983. The next prime is 21957043. The reversal of 21957030 is 3075912.

It is a super-3 number, since 3×21957030³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 21956985 and 21957003.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 172827 + ... + 172953.

It is an arithmetic number, because the mean of its divisors is an integer number (640224).

Almost surely, 2^21957030 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21957030, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30730752).

21957030 is an abundant number, since it is smaller than the sum of its proper divisors (39504474).

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

21957030 is a wasteful number, since it uses less digits than its factorization.

21957030 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270 (or 267 counting only the distinct ones).

The product of its (nonzero) digits is 1890, while the sum is 27.

The square root of 21957030 is about 4685.8329035509. The cubic root of 21957030 is about 280.0213844212.

The spelling of 21957030 in words is "twenty-one million, nine hundred fifty-seven thousand, thirty".