21952001 has 4 divisors (see below), whose sum is σ = 22030404. Its totient is φ = 21873600.

The previous prime is 21951997. The next prime is 21952003. The reversal of 21952001 is 10025912.

It is a Cunningham number, because it is equal to 280³+1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13512976 + 8439025 = 3676^2 + 2905^2 .

It is a cyclic number.

It is not a de Polignac number, because 21952001 - 2² = 21951997 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21952003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38780 + ... + 39341.

It is an arithmetic number, because the mean of its divisors is an integer number (5507601).

Almost surely, 2^21952001 is an apocalyptic number.

It is an amenable number.

21952001 is a deficient number, since it is larger than the sum of its proper divisors (78403).

21952001 is an equidigital number, since it uses as much as digits as its factorization.

21952001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78402.

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 21952001 is about 4685.2962553077. The cubic root of 21952001 is about 280.0000042517. Note that the first 5 decimals are identical.

Adding to 21952001 its reverse (10025912), we get a palindrome (31977913).

The spelling of 21952001 in words is "twenty-one million, nine hundred fifty-two thousand, one".