21721550215701 has 8 divisors (see below), whose sum is σ = 33099505090624. Its totient is φ = 12412314408960.

The previous prime is 21721550215697. The next prime is 21721550215759. The reversal of 21721550215701 is 10751205512712.

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

It is not a de Polignac number, because 21721550215701 - 2² = 21721550215697 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21721550215701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21721550215301) 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, 517179767020 + ... + 517179767061.

It is an arithmetic number, because the mean of its divisors is an integer number (4137438136328).

Almost surely, 2^{21721550215701} is an apocalyptic number.

21721550215701 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21721550215701 is a deficient number, since it is larger than the sum of its proper divisors (11377954874923).

21721550215701 is a wasteful number, since it uses less digits than its factorization.

21721550215701 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1034359534091.

The product of its (nonzero) digits is 49000, while the sum is 39.

The spelling of 21721550215701 in words is "twenty-one trillion, seven hundred twenty-one billion, five hundred fifty million, two hundred fifteen thousand, seven hundred one".