31424821 has 8 divisors (see below), whose sum is σ = 32382104. Its totient is φ = 30481920.

The previous prime is 31424807. The next prime is 31424867. The reversal of 31424821 is 12842413.

It can be written as a sum of positive squares in 4 ways, for example, as 7365796 + 24059025 = 2714^2 + 4905^2 .

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

It is a 5-Lehmer number, since φ(31424821) divides (31424821-1)⁵.

It is a cyclic number.

It is not a de Polignac number, because 31424821 - 2¹¹ = 31422773 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31424801) 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, 925 + ... + 7981.

It is an arithmetic number, because the mean of its divisors is an integer number (4047763).

Almost surely, 2^31424821 is an apocalyptic number.

It is an amenable number.

31424821 is a deficient number, since it is larger than the sum of its proper divisors (957283).

31424821 is an equidigital number, since it uses as much as digits as its factorization.

31424821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7191.

The product of its digits is 1536, while the sum is 25.

The square root of 31424821 is about 5605.7846016414. The cubic root of 31424821 is about 315.5665323323.

The spelling of 31424821 in words is "thirty-one million, four hundred twenty-four thousand, eight hundred twenty-one".