21177854801 has 6 divisors (see below), whose sum is σ = 21237139602. Its totient is φ = 21118735040.

The previous prime is 21177854783. The next prime is 21177854807. The reversal of 21177854801 is 10845877112.

It can be written as a sum of positive squares in only one way, i.e., 12465499201 + 8712355600 = 111649^2 + 93340^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21177854801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21177854807) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 46721 + ... + 211041.

It is an arithmetic number, because the mean of its divisors is an integer number (3539523267).

Almost surely, 2^21177854801 is an apocalyptic number.

It is an amenable number.

21177854801 is a deficient number, since it is larger than the sum of its proper divisors (59284801).

21177854801 is an frugal number, since it uses more digits than its factorization.

21177854801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165039 (or 164680 counting only the distinct ones).

The product of its (nonzero) digits is 125440, while the sum is 44.

The spelling of 21177854801 in words is "twenty-one billion, one hundred seventy-seven million, eight hundred fifty-four thousand, eight hundred one".