21651516434 has 48 divisors (see below), whose sum is σ = 34994146176. Its totient is φ = 10037795040.

The previous prime is 21651516431. The next prime is 21651516449. The reversal of 21651516434 is 43461515612.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21651516431) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4377767 + ... + 4382709.

It is an arithmetic number, because the mean of its divisors is an integer number (729044712).

Almost surely, 2^21651516434 is an apocalyptic number.

21651516434 is a deficient number, since it is larger than the sum of its proper divisors (13342629742).

21651516434 is a wasteful number, since it uses less digits than its factorization.

21651516434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5103 (or 5072 counting only the distinct ones).

The product of its digits is 86400, while the sum is 38.

The spelling of 21651516434 in words is "twenty-one billion, six hundred fifty-one million, five hundred sixteen thousand, four hundred thirty-four".