21101021002 has 4 divisors (see below), whose sum is σ = 31651531506. Its totient is φ = 10550510500.

The previous prime is 21101020991. The next prime is 21101021023. The reversal of 21101021002 is 20012010112.

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., 11652986601 + 9448034401 = 107949^2 + 97201^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21101021002.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5275255249 + ... + 5275255252.

Almost surely, 2^21101021002 is an apocalyptic number.

21101021002 is a deficient number, since it is larger than the sum of its proper divisors (10550510504).

21101021002 is a wasteful number, since it uses less digits than its factorization.

21101021002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10550510503.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21101021002 its reverse (20012010112), we get a palindrome (41113031114).

The spelling of 21101021002 in words is "twenty-one billion, one hundred one million, twenty-one thousand, two".