20381604111551 has 8 divisors (see below), whose sum is σ = 20442458091120. Its totient is φ = 20320752348288.

The previous prime is 20381604111541. The next prime is 20381604111571. The reversal of 20381604111551 is 15511140618302.

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

It is a cyclic number.

It is not a de Polignac number, because 20381604111551 - 2¹⁸ = 20381603849407 is a prime.

It is a super-4 number, since 4×20381604111551⁴ (a number of 54 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20381604111541) 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, 18881705 + ... + 19931933.

It is an arithmetic number, because the mean of its divisors is an integer number (2555307261390).

Almost surely, 2^{20381604111551} is an apocalyptic number.

20381604111551 is a deficient number, since it is larger than the sum of its proper divisors (60853979569).

20381604111551 is a wasteful number, since it uses less digits than its factorization.

20381604111551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1108153.

The product of its (nonzero) digits is 28800, while the sum is 38.

Adding to 20381604111551 its reverse (15511140618302), we get a palindrome (35892744729853).

The spelling of 20381604111551 in words is "twenty trillion, three hundred eighty-one billion, six hundred four million, one hundred eleven thousand, five hundred fifty-one".