21220139977 has 8 divisors (see below), whose sum is σ = 21542372064. Its totient is φ = 20898760608.

The previous prime is 21220139957. The next prime is 21220139999. The reversal of 21220139977 is 77993102212.

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

It is a cyclic number.

It is not a de Polignac number, because 21220139977 - 2⁷ = 21220139849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21220139957) 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 7 ways as a sum of consecutive naturals, for example, 162943 + ... + 262660.

It is an arithmetic number, because the mean of its divisors is an integer number (2692796508).

Almost surely, 2^21220139977 is an apocalyptic number.

It is an amenable number.

21220139977 is a deficient number, since it is larger than the sum of its proper divisors (322232087).

21220139977 is an equidigital number, since it uses as much as digits as its factorization.

21220139977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 426359.

The product of its (nonzero) digits is 95256, while the sum is 43.

The spelling of 21220139977 in words is "twenty-one billion, two hundred twenty million, one hundred thirty-nine thousand, nine hundred seventy-seven".