21958245 has 24 divisors (see below), whose sum is σ = 38634336. Its totient is φ = 11534688.

The previous prime is 21958229. The next prime is 21958267. The reversal of 21958245 is 54285912.

It is not a de Polignac number, because 21958245 - 2⁴ = 21958229 is a prime.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 627 + ... + 6656.

It is an arithmetic number, because the mean of its divisors is an integer number (1609764).

Almost surely, 2^21958245 is an apocalyptic number.

It is an amenable number.

21958245 is a deficient number, since it is larger than the sum of its proper divisors (16676091).

21958245 is a wasteful number, since it uses less digits than its factorization.

21958245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7361 (or 7358 counting only the distinct ones).

The product of its digits is 28800, while the sum is 36.

The square root of 21958245 is about 4685.9625478657. The cubic root of 21958245 is about 280.0265493533.

It can be divided in two parts, 2195 and 8245, that added together give a triangular number (10440 = T₁₄₄).

The spelling of 21958245 in words is "twenty-one million, nine hundred fifty-eight thousand, two hundred forty-five".