21123010 has 24 divisors (see below), whose sum is σ = 40395060. Its totient is φ = 7951104.

The previous prime is 21122971. The next prime is 21123013. The reversal of 21123010 is 1032112.

It can be written as a sum of positive squares in 6 ways, for example, as 14584761 + 6538249 = 3819^2 + 2557^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (21123013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 765 + ... + 6544.

Almost surely, 2^21123010 is an apocalyptic number.

21123010 is a deficient number, since it is larger than the sum of its proper divisors (19272050).

21123010 is a wasteful number, since it uses less digits than its factorization.

21123010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7350 (or 7333 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 21123010 is about 4595.9775891534. The cubic root of 21123010 is about 276.4300601259.

Adding to 21123010 its reverse (1032112), we get a palindrome (22155122).

The spelling of 21123010 in words is "twenty-one million, one hundred twenty-three thousand, ten".