20691748253940 has 24 divisors (see below), whose sum is σ = 57936895111200. Its totient is φ = 5517799534368.

The previous prime is 20691748253933. The next prime is 20691748253951. The reversal of 20691748253940 is 4935284719602.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (60), and also a Moran number because the ratio is a prime number: 344862470899 = 20691748253940 / (2 + 0 + 6 + 9 + 1 + 7 + 4 + 8 + 2 + 5 + 3 + 9 + 4 + 0).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 172431235390 + ... + 172431235509.

It is an arithmetic number, because the mean of its divisors is an integer number (2414037296300).

It is a 1-persistent number, because it is pandigital, but 2⋅20691748253940 = 41383496507880 is not.

Almost surely, 2^{20691748253940} is an apocalyptic number.

20691748253940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20691748253940 is an abundant number, since it is smaller than the sum of its proper divisors (37245146857260).

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

20691748253940 is a wasteful number, since it uses less digits than its factorization.

20691748253940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344862470911 (or 344862470909 counting only the distinct ones).

The product of its (nonzero) digits is 26127360, while the sum is 60.

The spelling of 20691748253940 in words is "twenty trillion, six hundred ninety-one billion, seven hundred forty-eight million, two hundred fifty-three thousand, nine hundred forty".