21240124 has 12 divisors (see below), whose sum is σ = 37220400. Its totient is φ = 10605728.

The previous prime is 21240101. The next prime is 21240133. The reversal of 21240124 is 42104212.

It is a super-2 number, since 2×21240124² = 902285735070752, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21240098 and 21240107.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 192 + ... + 6520.

It is an arithmetic number, because the mean of its divisors is an integer number (3101700).

Almost surely, 2^21240124 is an apocalyptic number.

It is an amenable number.

21240124 is a deficient number, since it is larger than the sum of its proper divisors (15980276).

21240124 is a wasteful number, since it uses less digits than its factorization.

21240124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7172 (or 7170 counting only the distinct ones).

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

The square root of 21240124 is about 4608.7009015557. The cubic root of 21240124 is about 276.9399966474.

Adding to 21240124 its reverse (42104212), we get a palindrome (63344336).

The spelling of 21240124 in words is "twenty-one million, two hundred forty thousand, one hundred twenty-four".