21421572247 has 16 divisors (see below), whose sum is σ = 21917347200. Its totient is φ = 20932116480.

The previous prime is 21421572233. The next prime is 21421572259. The reversal of 21421572247 is 74227512412.

It is not a de Polignac number, because 21421572247 - 2¹⁵ = 21421539479 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421572647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8018722 + ... + 8021392.

It is an arithmetic number, because the mean of its divisors is an integer number (1369834200).

Almost surely, 2^21421572247 is an apocalyptic number.

21421572247 is a deficient number, since it is larger than the sum of its proper divisors (495774953).

21421572247 is an equidigital number, since it uses as much as digits as its factorization.

21421572247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3786.

The product of its digits is 62720, while the sum is 37.

The spelling of 21421572247 in words is "twenty-one billion, four hundred twenty-one million, five hundred seventy-two thousand, two hundred forty-seven".