21949225 has 9 divisors (see below), whose sum is σ = 27246117. Its totient is φ = 17540640.

The previous prime is 21949223. The next prime is 21949229. The reversal of 21949225 is 52294912.

The square root of 21949225 is 4685.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 9018009 + 12931216 = 3003^2 + 3596^2 .

It is not a de Polignac number, because 21949225 - 2¹ = 21949223 is a prime.

It is a super-3 number, since 3×21949225³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21949223) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 22957 + ... + 23893.

Almost surely, 2^21949225 is an apocalyptic number.

21949225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21949225 is the 4685-th square number.

21949225 is the 2343-rd centered octagonal number.

It is an amenable number.

21949225 is a deficient number, since it is larger than the sum of its proper divisors (5296892).

21949225 is an frugal number, since it uses more digits than its factorization.

21949225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1884 (or 942 counting only the distinct ones).

The product of its digits is 12960, while the sum is 34.

The cubic root of 21949225 is about 279.9882010334.

The spelling of 21949225 in words is "twenty-one million, nine hundred forty-nine thousand, two hundred twenty-five".