21021002 has 4 divisors (see below), whose sum is σ = 31531506. Its totient is φ = 10510500.

The previous prime is 21021001. The next prime is 21021043. The reversal of 21021002 is 20012012.

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

It can be written as a sum of positive squares in only one way, i.e., 15689521 + 5331481 = 3961^2 + 2309^2 .

It is not an unprimeable number, because it can be changed into a prime (21021001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5255249 + ... + 5255252.

Almost surely, 2^21021002 is an apocalyptic number.

21021002 is a deficient number, since it is larger than the sum of its proper divisors (10510504).

21021002 is a wasteful number, since it uses less digits than its factorization.

21021002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10510503.

The product of its (nonzero) digits is 8, while the sum is 8.

The square root of 21021002 is about 4584.8666283764. The cubic root of 21021002 is about 275.9843598923.

Adding to 21021002 its reverse (20012012), we get a palindrome (41033014).

It can be divided in two parts, 210 and 21002, that added together give a palindrome (21212).

The spelling of 21021002 in words is "twenty-one million, twenty-one thousand, two".