40138821 has 40 divisors (see below), whose sum is σ = 62900640. Its totient is φ = 25481952.

The previous prime is 40138817. The next prime is 40138837. The reversal of 40138821 is 12883104.

It is not a de Polignac number, because 40138821 - 2² = 40138817 is a prime.

It is a super-2 number, since 2×40138821² = 3222249902540082, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40138801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 176710 + ... + 176936.

It is an arithmetic number, because the mean of its divisors is an integer number (1572516).

Almost surely, 2^40138821 is an apocalyptic number.

It is an amenable number.

40138821 is a deficient number, since it is larger than the sum of its proper divisors (22761819).

40138821 is a wasteful number, since it uses less digits than its factorization.

40138821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 335 (or 326 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 40138821 is about 6335.5205784529. The cubic root of 40138821 is about 342.3903668144.

The spelling of 40138821 in words is "forty million, one hundred thirty-eight thousand, eight hundred twenty-one".