20953555501 has 4 divisors (see below), whose sum is σ = 20961438400. Its totient is φ = 20945672604.

The previous prime is 20953555499. The next prime is 20953555517. The reversal of 20953555501 is 10555535902.

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, and also an emirpimes, since its reverse is a distinct semiprime: 10555535902 = 2 ⋅5277767951.

It is a cyclic number.

It is not a de Polignac number, because 20953555501 - 2¹ = 20953555499 is a prime.

It is a super-2 number, since 2×20953555501² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20953555561) 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, 3937461 + ... + 3942778.

It is an arithmetic number, because the mean of its divisors is an integer number (5240359600).

Almost surely, 2^20953555501 is an apocalyptic number.

It is an amenable number.

20953555501 is a deficient number, since it is larger than the sum of its proper divisors (7882899).

20953555501 is an equidigital number, since it uses as much as digits as its factorization.

20953555501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7882898.

The product of its (nonzero) digits is 168750, while the sum is 40.

The spelling of 20953555501 in words is "twenty billion, nine hundred fifty-three million, five hundred fifty-five thousand, five hundred one".