21240710157 has 4 divisors (see below), whose sum is σ = 28320946880. Its totient is φ = 14160473436.

The previous prime is 21240710131. The next prime is 21240710159. The reversal of 21240710157 is 75101704212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21240710157 - 2¹¹ = 21240708109 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 (21240710159) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3540118357 + ... + 3540118362.

It is an arithmetic number, because the mean of its divisors is an integer number (7080236720).

Almost surely, 2^21240710157 is an apocalyptic number.

It is an amenable number.

21240710157 is a deficient number, since it is larger than the sum of its proper divisors (7080236723).

21240710157 is an equidigital number, since it uses as much as digits as its factorization.

21240710157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7080236722.

The product of its (nonzero) digits is 3920, while the sum is 30.

The spelling of 21240710157 in words is "twenty-one billion, two hundred forty million, seven hundred ten thousand, one hundred fifty-seven".