21015146 has 16 divisors (see below), whose sum is σ = 32997888. Its totient is φ = 10018800.

The previous prime is 21015143. The next prime is 21015161. The reversal of 21015146 is 64151012.

It is a super-2 number, since 2×21015146² = 883272722802632, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21015143) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20711 + ... + 21701.

It is an arithmetic number, because the mean of its divisors is an integer number (2062368).

Almost surely, 2^21015146 is an apocalyptic number.

21015146 is a deficient number, since it is larger than the sum of its proper divisors (11982742).

21015146 is a wasteful number, since it uses less digits than its factorization.

21015146 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1477.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 21015146 is about 4584.2279611730. The cubic root of 21015146 is about 275.9587297390.

Adding to 21015146 its reverse (64151012), we get a palindrome (85166158).

The spelling of 21015146 in words is "twenty-one million, fifteen thousand, one hundred forty-six".