20770621 has 4 divisors (see below), whose sum is σ = 20783644. Its totient is φ = 20757600.

The previous prime is 20770619. The next prime is 20770637. The reversal of 20770621 is 12607702.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 168100 + 20602521 = 410^2 + 4539^2 .

It is a 3-Lehmer number, since φ(20770621) divides (20770621-1)³.

It is a cyclic number.

It is not a de Polignac number, because 20770621 - 2¹ = 20770619 is a prime.

It is a deceptive number, since it divides R_20770620.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20770681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3720 + ... + 7441.

It is an arithmetic number, because the mean of its divisors is an integer number (5195911).

It is a Poulet number, since it divides 2^20770620-1.

Almost surely, 2^20770621 is an apocalyptic number.

It is an amenable number.

20770621 is a deficient number, since it is larger than the sum of its proper divisors (13023).

20770621 is a wasteful number, since it uses less digits than its factorization.

20770621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13022.

The product of its (nonzero) digits is 1176, while the sum is 25.

The square root of 20770621 is about 4557.4796763123. The cubic root of 20770621 is about 274.8842311606.

The spelling of 20770621 in words is "twenty million, seven hundred seventy thousand, six hundred twenty-one".