21430441978 has 16 divisors (see below), whose sum is σ = 37130819904. Its totient is φ = 9168103360.

The previous prime is 21430441957. The next prime is 21430441979. The reversal of 21430441978 is 87914403412.

It is a super-3 number, since 3×21430441978³ (a number of 32 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21430441979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28649950 + ... + 28650697.

It is an arithmetic number, because the mean of its divisors is an integer number (2320676244).

Almost surely, 2^21430441978 is an apocalyptic number.

21430441978 is a deficient number, since it is larger than the sum of its proper divisors (15700377926).

21430441978 is a wasteful number, since it uses less digits than its factorization.

21430441978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57300677.

The product of its (nonzero) digits is 193536, while the sum is 43.

The spelling of 21430441978 in words is "twenty-one billion, four hundred thirty million, four hundred forty-one thousand, nine hundred seventy-eight".