21951075 has 18 divisors (see below), whose sum is σ = 36359652. Its totient is φ = 11685600.

The previous prime is 21951073. The next prime is 21951079. The reversal of 21951075 is 57015912.

It is not a de Polignac number, because 21951075 - 2¹ = 21951073 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21951071) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 40305 + ... + 40845.

Almost surely, 2^21951075 is an apocalyptic number.

21951075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21951075 is a deficient number, since it is larger than the sum of its proper divisors (14408577).

21951075 is an frugal number, since it uses more digits than its factorization.

21951075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1095 (or 549 counting only the distinct ones).

The product of its (nonzero) digits is 3150, while the sum is 30.

The square root of 21951075 is about 4685.1974344738. The cubic root of 21951075 is about 279.9960671216.

Adding to 21951075 its reverse (57015912), we get a palindrome (78966987).

The spelling of 21951075 in words is "twenty-one million, nine hundred fifty-one thousand, seventy-five".