20551433251391 has 8 divisors (see below), whose sum is σ = 23499892266144. Its totient is φ = 17606109231360.

The previous prime is 20551433251343. The next prime is 20551433251411. The reversal of 20551433251391 is 19315233415502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20551433251391 is a prime.

It is a super-2 number, since 2×20551433251391² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20551433251091) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 783734630 + ... + 783760851.

It is an arithmetic number, because the mean of its divisors is an integer number (2937486533268).

Almost surely, 2^{20551433251391} is an apocalyptic number.

20551433251391 is a deficient number, since it is larger than the sum of its proper divisors (2948459014753).

20551433251391 is a wasteful number, since it uses less digits than its factorization.

20551433251391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1567497361.

The product of its (nonzero) digits is 486000, while the sum is 44.

Adding to 20551433251391 its reverse (19315233415502), we get a palindrome (39866666666893).

The spelling of 20551433251391 in words is "twenty trillion, five hundred fifty-one billion, four hundred thirty-three million, two hundred fifty-one thousand, three hundred ninety-one".