20757218008081 has 27 divisors (see below), whose sum is σ = 21270757524219. Its totient is φ = 20256016014000.

The previous prime is 20757218008069. The next prime is 20757218008097. The reversal of 20757218008081 is 18080081275702.

The square root of 20757218008081 is 4556009.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 19943289255681 + 813928752400 = 4465791^2 + 902180^2 .

It is not a de Polignac number, because 20757218008081 - 2²¹ = 20757215910929 is a prime.

It is a super-2 number, since 2×20757218008081² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20757218005081) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 36352395526 + ... + 36352396096.

Almost surely, 2^{20757218008081} is an apocalyptic number.

20757218008081 is the 4556009-th square number.

20757218008081 is the 2278005-th centered octagonal number.

It is an amenable number.

20757218008081 is a deficient number, since it is larger than the sum of its proper divisors (513539516138).

20757218008081 is an frugal number, since it uses more digits than its factorization.

20757218008081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1502 (or 751 counting only the distinct ones).

The product of its (nonzero) digits is 501760, while the sum is 49.

The spelling of 20757218008081 in words is "twenty trillion, seven hundred fifty-seven billion, two hundred eighteen million, eight thousand, eighty-one".