21401850645 has 32 divisors (see below), whose sum is σ = 43483127040. Its totient is φ = 9783702720.

The previous prime is 21401850619. The next prime is 21401850683. The reversal of 21401850645 is 54605810412.

It is a happy number.

21401850645 is a `hidden beast` number, since 2 + 1 + 4 + 0 + 1 + 8 + 5 + 0 + 645 = 666.

It is not a de Polignac number, because 21401850645 - 2⁷ = 21401850517 is a prime.

It is a super-2 number, since 2×21401850645² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11322786 + ... + 11324675.

It is an arithmetic number, because the mean of its divisors is an integer number (1358847720).

Almost surely, 2^21401850645 is an apocalyptic number.

It is an amenable number.

21401850645 is an abundant number, since it is smaller than the sum of its proper divisors (22081276395).

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

21401850645 is a wasteful number, since it uses less digits than its factorization.

21401850645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22647482 (or 22647476 counting only the distinct ones).

The product of its (nonzero) digits is 38400, while the sum is 36.

The spelling of 21401850645 in words is "twenty-one billion, four hundred one million, eight hundred fifty thousand, six hundred forty-five".