30640821 has 8 divisors (see below), whose sum is σ = 40892544. Its totient is φ = 20408160.

The previous prime is 30640781. The next prime is 30640823. The reversal of 30640821 is 12804603.

It is a happy number.

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

It is not a de Polignac number, because 30640821 - 2¹³ = 30632629 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 30640791 and 30640800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30640823) 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, 456 + ... + 7841.

It is an arithmetic number, because the mean of its divisors is an integer number (5111568).

Almost surely, 2^30640821 is an apocalyptic number.

It is an amenable number.

30640821 is a deficient number, since it is larger than the sum of its proper divisors (10251723).

30640821 is a wasteful number, since it uses less digits than its factorization.

30640821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9531.

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 30640821 is about 5535.4151605819. The cubic root of 30640821 is about 312.9201040007.

The spelling of 30640821 in words is "thirty million, six hundred forty thousand, eight hundred twenty-one".