21953478 has 16 divisors (see below), whose sum is σ = 44928576. Its totient is φ = 7147560.

The previous prime is 21953471. The next prime is 21953479. The reversal of 21953478 is 87435912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21953471) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42288 + ... + 42803.

It is an arithmetic number, because the mean of its divisors is an integer number (2808036).

Almost surely, 2^21953478 is an apocalyptic number.

21953478 is an abundant number, since it is smaller than the sum of its proper divisors (22975098).

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

21953478 is a wasteful number, since it uses less digits than its factorization.

21953478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85139.

The product of its digits is 60480, while the sum is 39.

The square root of 21953478 is about 4685.4538734257. The cubic root of 21953478 is about 280.0062838726.

The spelling of 21953478 in words is "twenty-one million, nine hundred fifty-three thousand, four hundred seventy-eight".