21123402 has 32 divisors (see below), whose sum is σ = 44851200. Its totient is φ = 6613488.

The previous prime is 21123391. The next prime is 21123457. The reversal of 21123402 is 20432112.

It is a super-2 number, since 2×21123402² = 892396224107208, which contains 22 as substring.

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, 13749 + ... + 15207.

It is an arithmetic number, because the mean of its divisors is an integer number (1401600).

Almost surely, 2^21123402 is an apocalyptic number.

21123402 is an abundant number, since it is smaller than the sum of its proper divisors (23727798).

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

21123402 is a wasteful number, since it uses less digits than its factorization.

21123402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1610.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21123402 is about 4596.0202349424. The cubic root of 21123402 is about 276.4317701081.

Adding to 21123402 its reverse (20432112), we get a palindrome (41555514).

The spelling of 21123402 in words is "twenty-one million, one hundred twenty-three thousand, four hundred two".