21440131657 has 16 divisors (see below), whose sum is σ = 24599135232. Its totient is φ = 18305306640.

The previous prime is 21440131597. The next prime is 21440131663. The reversal of 21440131657 is 75613104412.

It is a cyclic number.

It is not a de Polignac number, because 21440131657 - 2¹¹ = 21440129609 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21440131357) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1913682 + ... + 1924852.

It is an arithmetic number, because the mean of its divisors is an integer number (1537445952).

Almost surely, 2^21440131657 is an apocalyptic number.

It is an amenable number.

21440131657 is a deficient number, since it is larger than the sum of its proper divisors (3159003575).

21440131657 is a wasteful number, since it uses less digits than its factorization.

21440131657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12228.

The product of its (nonzero) digits is 20160, while the sum is 34.

The spelling of 21440131657 in words is "twenty-one billion, four hundred forty million, one hundred thirty-one thousand, six hundred fifty-seven".