20521630 has 8 divisors (see below), whose sum is σ = 36938952. Its totient is φ = 8208648.

The previous prime is 20521609. The next prime is 20521639. The reversal of 20521630 is 3612502.

It is a happy number.

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

It is a super-2 number, since 2×20521630² = 842274595713800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20521598 and 20521607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20521639) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1026072 + ... + 1026091.

It is an arithmetic number, because the mean of its divisors is an integer number (4617369).

Almost surely, 2^20521630 is an apocalyptic number.

20521630 is a deficient number, since it is larger than the sum of its proper divisors (16417322).

20521630 is a wasteful number, since it uses less digits than its factorization.

20521630 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2052170.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 20521630 is about 4530.0805732349. The cubic root of 20521630 is about 273.7814069871.

The spelling of 20521630 in words is "twenty million, five hundred twenty-one thousand, six hundred thirty".