20406155501556 has 108 divisors (see below), whose sum is σ = 56820813461412. Its totient is φ = 6170269248000.

The previous prime is 20406155501503. The next prime is 20406155501569. The reversal of 20406155501556 is 65510555160402.

It is a happy number.

20406155501556 is a `hidden beast` number, since 2 + 0 + 40 + 6 + 1 + 5 + 5 + 50 + 1 + 556 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 4844550669156 + 15561604832400 = 2201034^2 + 3944820^2 .

It is a super-2 number, since 2×20406155501556² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3072805 + ... + 7089036.

Almost surely, 2^{20406155501556} is an apocalyptic number.

It is an amenable number.

20406155501556 is an abundant number, since it is smaller than the sum of its proper divisors (36414657959856).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20406155501556 is a wasteful number, since it uses less digits than its factorization.

20406155501556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10162334 (or 10162318 counting only the distinct ones).

The product of its (nonzero) digits is 900000, while the sum is 45.

The spelling of 20406155501556 in words is "twenty trillion, four hundred six billion, one hundred fifty-five million, five hundred one thousand, five hundred fifty-six".