20021521543451 has 8 divisors (see below), whose sum is σ = 20354967554880. Its totient is φ = 19689093688968.

The previous prime is 20021521543399. The next prime is 20021521543481. The reversal of 20021521543451 is 15434512512002.

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

It is a cyclic number.

It is not a de Polignac number, because 20021521543451 - 2²² = 20021517349147 is a prime.

It is a super-2 number, since 2×20021521543451² (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 (20021521543481) 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, 254499581 + ... + 254578238.

It is an arithmetic number, because the mean of its divisors is an integer number (2544370944360).

Almost surely, 2^{20021521543451} is an apocalyptic number.

20021521543451 is a deficient number, since it is larger than the sum of its proper divisors (333446011429).

20021521543451 is an equidigital number, since it uses as much as digits as its factorization.

20021521543451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 509078473.

The product of its (nonzero) digits is 48000, while the sum is 35.

The spelling of 20021521543451 in words is "twenty trillion, twenty-one billion, five hundred twenty-one million, five hundred forty-three thousand, four hundred fifty-one".