21291002 has 8 divisors (see below), whose sum is σ = 32253012. Its totient is φ = 10540000.

The previous prime is 21290999. The next prime is 21291007. The reversal of 21291002 is 20019212.

It can be written as a sum of positive squares in 2 ways, for example, as 21169201 + 121801 = 4601^2 + 349^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21291007) 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, 52499 + ... + 52902.

Almost surely, 2^21291002 is an apocalyptic number.

21291002 is a deficient number, since it is larger than the sum of its proper divisors (10962010).

21291002 is a wasteful number, since it uses less digits than its factorization.

21291002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105504.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 21291002 is about 4614.2173767607. The cubic root of 21291002 is about 277.1609451019.

The spelling of 21291002 in words is "twenty-one million, two hundred ninety-one thousand, two".