21919425 has 36 divisors (see below), whose sum is σ = 39778704. Its totient is φ = 10562400.

The previous prime is 21919411. The next prime is 21919427. The reversal of 21919425 is 52491912.

It is not a de Polignac number, because 21919425 - 2⁵ = 21919393 is a prime.

It is a super-2 number, since 2×21919425² = 960922384661250, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (21919427) 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 35 ways as a sum of consecutive naturals, for example, 134394 + ... + 134556.

It is an arithmetic number, because the mean of its divisors is an integer number (1104964).

Almost surely, 2^21919425 is an apocalyptic number.

21919425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21919425 is a deficient number, since it is larger than the sum of its proper divisors (17859279).

21919425 is a wasteful number, since it uses less digits than its factorization.

21919425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350 (or 182 counting only the distinct ones).

The product of its digits is 6480, while the sum is 33.

The square root of 21919425 is about 4681.8185569285. The cubic root of 21919425 is about 279.8614322866.

Multiplying 21919425 by its sum of digits (33), we get a square (723341025 = 26895²).

21919425 divided by its sum of digits (33) gives a square (664225 = 815²).

The spelling of 21919425 in words is "twenty-one million, nine hundred nineteen thousand, four hundred twenty-five".