21958100 has 36 divisors (see below), whose sum is σ = 49725984. Its totient is φ = 8400480.

The previous prime is 21958093. The next prime is 21958103. The reversal of 21958100 is 185912.

It is a happy number.

It is a super-2 number, since 2×21958100² = 964316311220000, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21958100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21958103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2474 + ... + 7073.

Almost surely, 2^21958100 is an apocalyptic number.

21958100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21958100 is an abundant number, since it is smaller than the sum of its proper divisors (27767884).

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

21958100 is a wasteful number, since it uses less digits than its factorization.

21958100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9584 (or 9577 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 21958100 is about 4685.9470760989. The cubic root of 21958100 is about 280.0259329722.

The spelling of 21958100 in words is "twenty-one million, nine hundred fifty-eight thousand, one hundred".