20621885 has 4 divisors (see below), whose sum is σ = 24746268. Its totient is φ = 16497504.

The previous prime is 20621827. The next prime is 20621891. The reversal of 20621885 is 58812602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58812602 = 2 ⋅29406301.

It can be written as a sum of positive squares in 2 ways, for example, as 12264004 + 8357881 = 3502^2 + 2891^2 .

It is a cyclic number.

It is not a de Polignac number, because 20621885 - 2¹⁰ = 20620861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2062184 + ... + 2062193.

It is an arithmetic number, because the mean of its divisors is an integer number (6186567).

Almost surely, 2^20621885 is an apocalyptic number.

It is an amenable number.

20621885 is a deficient number, since it is larger than the sum of its proper divisors (4124383).

20621885 is an equidigital number, since it uses as much as digits as its factorization.

20621885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4124382.

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 20621885 is about 4541.1325679835. The cubic root of 20621885 is about 274.2265207266.

The spelling of 20621885 in words is "twenty million, six hundred twenty-one thousand, eight hundred eighty-five".