21012510 has 32 divisors (see below), whose sum is σ = 53397792. Its totient is φ = 5273600.

The previous prime is 21012503. The next prime is 21012517. The reversal of 21012510 is 1521012.

21012510 = 2048² + 2049² + ... + 2052².

It is an interprime number because it is at equal distance from previous prime (21012503) and next prime (21012517).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012517) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20091 + ... + 21110.

It is an arithmetic number, because the mean of its divisors is an integer number (1668681).

Almost surely, 2^21012510 is an apocalyptic number.

21012510 is an abundant number, since it is smaller than the sum of its proper divisors (32385282).

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

21012510 is a wasteful number, since it uses less digits than its factorization.

21012510 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41228.

The product of its (nonzero) digits is 20, while the sum is 12.

The square root of 21012510 is about 4583.9404446393. The cubic root of 21012510 is about 275.9471911146.

Adding to 21012510 its reverse (1521012), we get a palindrome (22533522).

It can be divided in two parts, 210 and 12510, that added together give a triangular number (12720 = T₁₅₉).

The spelling of 21012510 in words is "twenty-one million, twelve thousand, five hundred ten".