901821 has 8 divisors (see below), whose sum is σ = 1241344. Its totient is φ = 581760.

The previous prime is 901819. The next prime is 901841. The reversal of 901821 is 128109.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 901821 - 2¹ = 901819 is a prime.

It is a super-2 number, since 2×901821² = 1626562232082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (901811) 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, 4756 + ... + 4941.

It is an arithmetic number, because the mean of its divisors is an integer number (155168).

2⁹⁰¹⁸²¹ is an apocalyptic number.

It is an amenable number.

901821 is a deficient number, since it is larger than the sum of its proper divisors (339523).

901821 is a wasteful number, since it uses less digits than its factorization.

901821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9731.

The product of its (nonzero) digits is 144, while the sum is 21.

The square root of 901821 is about 949.6425643367. The cubic root of 901821 is about 96.6140114873.

The spelling of 901821 in words is "nine hundred one thousand, eight hundred twenty-one".