20406155521 has 8 divisors (see below), whose sum is σ = 20740299680. Its totient is φ = 20073487392.

The previous prime is 20406155507. The next prime is 20406155531. The reversal of 20406155521 is 12555160402.

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 20406155521 - 2¹³ = 20406147329 is a prime.

It is a super-2 number, since 2×20406155521² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20406155531) 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, 341115 + ... + 396448.

It is an arithmetic number, because the mean of its divisors is an integer number (2592537460).

Almost surely, 2^20406155521 is an apocalyptic number.

It is an amenable number.

20406155521 is a deficient number, since it is larger than the sum of its proper divisors (334144159).

20406155521 is an equidigital number, since it uses as much as digits as its factorization.

20406155521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 738015.

The product of its (nonzero) digits is 12000, while the sum is 31.

The spelling of 20406155521 in words is "twenty billion, four hundred six million, one hundred fifty-five thousand, five hundred twenty-one".