21402124 has 6 divisors (see below), whose sum is σ = 37453724. Its totient is φ = 10701060.

The previous prime is 21402119. The next prime is 21402137. The reversal of 21402124 is 42120412.

It is a super-2 number, since 2×21402124² = 916101823422752, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21402098 and 21402107.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2675262 + ... + 2675269.

Almost surely, 2^21402124 is an apocalyptic number.

It is an amenable number.

21402124 is a deficient number, since it is larger than the sum of its proper divisors (16051600).

21402124 is a wasteful number, since it uses less digits than its factorization.

21402124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5350535 (or 5350533 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 21402124 is about 4626.2429681114. The cubic root of 21402124 is about 277.6422947956.

Adding to 21402124 its reverse (42120412), we get a palindrome (63522536).

The spelling of 21402124 in words is "twenty-one million, four hundred two thousand, one hundred twenty-four".