400021726545 has 36 divisors (see below), whose sum is σ = 806574424500. Its totient is φ = 182867073984.

The previous prime is 400021726543. The next prime is 400021726579. The reversal of 400021726545 is 545627120004.

It is a happy number.

400021726545 is a `hidden beast` number, since 40 + 0 + 0 + 2 + 1 + 72 + 6 + 545 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 306056794176 + 93964932369 = 553224^2 + 306537^2 .

It is not a de Polignac number, because 400021726545 - 2¹ = 400021726543 is a prime.

It is not an unprimeable number, because it can be changed into a prime (400021726543) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 90705670 + ... + 90710079.

It is an arithmetic number, because the mean of its divisors is an integer number (22404845125).

Almost surely, 2^400021726545 is an apocalyptic number.

400021726545 is a gapful number since it is divisible by the number (45) formed by its first and last digit.

It is an amenable number.

400021726545 is an abundant number, since it is smaller than the sum of its proper divisors (406552697955).

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

400021726545 is a wasteful number, since it uses less digits than its factorization.

400021726545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181415774 (or 181415764 counting only the distinct ones).

The product of its (nonzero) digits is 67200, while the sum is 36.

Adding to 400021726545 its reverse (545627120004), we get a palindrome (945648846549).

The spelling of 400021726545 in words is "four hundred billion, twenty-one million, seven hundred twenty-six thousand, five hundred forty-five".