21425431515 has 32 divisors (see below), whose sum is σ = 35186227200. Its totient is φ = 11127498624.

The previous prime is 21425431471. The next prime is 21425431519. The reversal of 21425431515 is 51513452412.

It is not a de Polignac number, because 21425431515 - 2⁶ = 21425431451 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21425431519) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 63937 + ... + 216653.

It is an arithmetic number, because the mean of its divisors is an integer number (1099569600).

Almost surely, 2^21425431515 is an apocalyptic number.

21425431515 is a deficient number, since it is larger than the sum of its proper divisors (13760795685).

21425431515 is a wasteful number, since it uses less digits than its factorization.

21425431515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152971.

The product of its digits is 24000, while the sum is 33.

Adding to 21425431515 its reverse (51513452412), we get a palindrome (72938883927).

The spelling of 21425431515 in words is "twenty-one billion, four hundred twenty-five million, four hundred thirty-one thousand, five hundred fifteen".