21025001 has 12 divisors (see below), whose sum is σ = 22402800. Its totient is φ = 19727928.

The previous prime is 21024961. The next prime is 21025019. The reversal of 21025001 is 10052012.

It is a de Polignac number, because none of the positive numbers 2^k-21025001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21025021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 49970 + ... + 50388.

It is an arithmetic number, because the mean of its divisors is an integer number (1866900).

Almost surely, 2^21025001 is an apocalyptic number.

It is an amenable number.

21025001 is a deficient number, since it is larger than the sum of its proper divisors (1377799).

21025001 is a wasteful number, since it uses less digits than its factorization.

21025001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 596 (or 577 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 11.

The square root of 21025001 is about 4585.3027162882. The cubic root of 21025001 is about 276.0018597158.

Adding to 21025001 its reverse (10052012), we get a palindrome (31077013).

The spelling of 21025001 in words is "twenty-one million, twenty-five thousand, one".