21959028 has 72 divisors (see below), whose sum is σ = 68327168. Its totient is φ = 5790528.

The previous prime is 21959017. The next prime is 21959029. The reversal of 21959028 is 82095912.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21958983 and 21959001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21959029) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 76 + ... + 6627.

Almost surely, 2^21959028 is an apocalyptic number.

21959028 is a gapful number since it is divisible by the number (28) 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 21959028, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34163584).

21959028 is an abundant number, since it is smaller than the sum of its proper divisors (46368140).

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

21959028 is a wasteful number, since it uses less digits than its factorization.

21959028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6733 (or 6728 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 21959028 is about 4686.0460945236. The cubic root of 21959028 is about 280.0298777641.

The spelling of 21959028 in words is "twenty-one million, nine hundred fifty-nine thousand, twenty-eight".