21424953 has 16 divisors (see below), whose sum is σ = 31262400. Its totient is φ = 12943680.

The previous prime is 21424943. The next prime is 21424957. The reversal of 21424953 is 35942412.

It is not a de Polignac number, because 21424953 - 2¹⁶ = 21359417 is a prime.

It is a super-2 number, since 2×21424953² = 918057222104418, 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 21424953.

It is not an unprimeable number, because it can be changed into a prime (21424957) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12003 + ... + 13671.

It is an arithmetic number, because the mean of its divisors is an integer number (1953900).

Almost surely, 2^21424953 is an apocalyptic number.

It is an amenable number.

21424953 is a deficient number, since it is larger than the sum of its proper divisors (9837447).

21424953 is a wasteful number, since it uses less digits than its factorization.

21424953 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2072.

The product of its digits is 8640, while the sum is 30.

The square root of 21424953 is about 4628.7096474071. The cubic root of 21424953 is about 277.7409772700.

The spelling of 21424953 in words is "twenty-one million, four hundred twenty-four thousand, nine hundred fifty-three".