21011898 has 32 divisors (see below), whose sum is σ = 44914176. Its totient is φ = 6530048.

The previous prime is 21011873. The next prime is 21011917. The reversal of 21011898 is 89811012.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10615 + ... + 12437.

It is an arithmetic number, because the mean of its divisors is an integer number (1403568).

Almost surely, 2^21011898 is an apocalyptic number.

21011898 is an abundant number, since it is smaller than the sum of its proper divisors (23902278).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21011898 is a wasteful number, since it uses less digits than its factorization.

21011898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1958.

The product of its (nonzero) digits is 1152, while the sum is 30.

The square root of 21011898 is about 4583.8736893593. The cubic root of 21011898 is about 275.9445120547.

The spelling of 21011898 in words is "twenty-one million, eleven thousand, eight hundred ninety-eight".