21155351015623 has 16 divisors (see below), whose sum is σ = 23460811269120. Its totient is φ = 18913703608800.

The previous prime is 21155351015621. The next prime is 21155351015629. The reversal of 21155351015623 is 32651015355112.

It is not a de Polignac number, because 21155351015623 - 2¹ = 21155351015621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155351015621) 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, 1406418 + ... + 6654976.

It is an arithmetic number, because the mean of its divisors is an integer number (1466300704320).

Almost surely, 2^{21155351015623} is an apocalyptic number.

21155351015623 is a deficient number, since it is larger than the sum of its proper divisors (2305460253497).

21155351015623 is a wasteful number, since it uses less digits than its factorization.

21155351015623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5254638.

The product of its (nonzero) digits is 135000, while the sum is 40.

The spelling of 21155351015623 in words is "twenty-one trillion, one hundred fifty-five billion, three hundred fifty-one million, fifteen thousand, six hundred twenty-three".