21506100771601 has 4 divisors (see below), whose sum is σ = 21510793357632. Its totient is φ = 21501408185572.

The previous prime is 21506100771553. The next prime is 21506100771703. The reversal of 21506100771601 is 10617700160512.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21506100771601 - 2¹¹ = 21506100769553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21506100771101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2346286141 + ... + 2346295306.

It is an arithmetic number, because the mean of its divisors is an integer number (5377698339408).

Almost surely, 2^{21506100771601} is an apocalyptic number.

It is an amenable number.

21506100771601 is a deficient number, since it is larger than the sum of its proper divisors (4692586031).

21506100771601 is an equidigital number, since it uses as much as digits as its factorization.

21506100771601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4692586030.

The product of its (nonzero) digits is 17640, while the sum is 37.

The spelling of 21506100771601 in words is "twenty-one trillion, five hundred six billion, one hundred million, seven hundred seventy-one thousand, six hundred one".