21001430 has 32 divisors (see below), whose sum is σ = 39076128. Its totient is φ = 8121600.

The previous prime is 21001429. The next prime is 21001447. The reversal of 21001430 is 3410012.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74069 + ... + 74351.

It is an arithmetic number, because the mean of its divisors is an integer number (1221129).

Almost surely, 2^21001430 is an apocalyptic number.

21001430 is a deficient number, since it is larger than the sum of its proper divisors (18074698).

21001430 is a wasteful number, since it uses less digits than its factorization.

21001430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 512.

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21001430 is about 4582.7317180913. The cubic root of 21001430 is about 275.8986798159.

Adding to 21001430 its reverse (3410012), we get a palindrome (24411442).

The spelling of 21001430 in words is "twenty-one million, one thousand, four hundred thirty".