21040242345 has 32 divisors (see below), whose sum is σ = 38611491840. Its totient is φ = 10859477760.

The previous prime is 21040242337. The next prime is 21040242383. The reversal of 21040242345 is 54324204012.

21040242345 is a `hidden beast` number, since 21 + 0 + 402 + 4 + 234 + 5 = 666.

It is not a de Polignac number, because 21040242345 - 2³ = 21040242337 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2509584 + ... + 2517953.

It is an arithmetic number, because the mean of its divisors is an integer number (1206609120).

Almost surely, 2^21040242345 is an apocalyptic number.

It is an amenable number.

21040242345 is a deficient number, since it is larger than the sum of its proper divisors (17571249495).

21040242345 is a wasteful number, since it uses less digits than its factorization.

21040242345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5027582 (or 5027576 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 27.

Adding to 21040242345 its reverse (54324204012), we get a palindrome (75364446357).

The spelling of 21040242345 in words is "twenty-one billion, forty million, two hundred forty-two thousand, three hundred forty-five".