90400821 has 16 divisors (see below), whose sum is σ = 139696128. Its totient is φ = 50929200.

The previous prime is 90400819. The next prime is 90400847. The reversal of 90400821 is 12800409.

It is not a de Polignac number, because 90400821 - 2¹ = 90400819 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 90400791 and 90400800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90400811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28825 + ... + 31806.

It is an arithmetic number, because the mean of its divisors is an integer number (8731008).

Almost surely, 2^90400821 is an apocalyptic number.

It is an amenable number.

90400821 is a deficient number, since it is larger than the sum of its proper divisors (49295307).

90400821 is a wasteful number, since it uses less digits than its factorization.

90400821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60712.

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 90400821 is about 9507.9346337677. The cubic root of 90400821 is about 448.8047639706.

The spelling of 90400821 in words is "ninety million, four hundred thousand, eight hundred twenty-one".