19700636021 has 4 divisors (see below), whose sum is σ = 21491602944. Its totient is φ = 17909669100.

The previous prime is 19700635991. The next prime is 19700636023. The reversal of 19700636021 is 12063600791.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19700636021 - 2²⁶ = 19633527157 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 (19700636023) 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, 895483445 + ... + 895483466.

It is an arithmetic number, because the mean of its divisors is an integer number (5372900736).

Almost surely, 2^19700636021 is an apocalyptic number.

19700636021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

19700636021 is a deficient number, since it is larger than the sum of its proper divisors (1790966923).

19700636021 is a wasteful number, since it uses less digits than its factorization.

19700636021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1790966922.

The product of its (nonzero) digits is 13608, while the sum is 35.

The spelling of 19700636021 in words is "nineteen billion, seven hundred million, six hundred thirty-six thousand, twenty-one".