21521557130 has 16 divisors (see below), whose sum is σ = 38741497344. Its totient is φ = 8608024080.

The previous prime is 21521557121. The next prime is 21521557139. The reversal of 21521557130 is 3175512512.

It is an interprime number because it is at equal distance from previous prime (21521557121) and next prime (21521557139).

It is not an unprimeable number, because it can be changed into a prime (21521557139) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 94319 + ... + 227901.

It is an arithmetic number, because the mean of its divisors is an integer number (2421343584).

Almost surely, 2^21521557130 is an apocalyptic number.

21521557130 is a deficient number, since it is larger than the sum of its proper divisors (17219940214).

21521557130 is a wasteful number, since it uses less digits than its factorization.

21521557130 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149701.

The product of its (nonzero) digits is 10500, while the sum is 32.

The spelling of 21521557130 in words is "twenty-one billion, five hundred twenty-one million, five hundred fifty-seven thousand, one hundred thirty".