21247157461 has 8 divisors (see below), whose sum is σ = 21358232064. Its totient is φ = 21136253280.

The previous prime is 21247157401. The next prime is 21247157479. The reversal of 21247157461 is 16475174212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21247157461 - 2⁹ = 21247156949 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 (21247157401) 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, 211326 + ... + 295216.

It is an arithmetic number, because the mean of its divisors is an integer number (2669779008).

Almost surely, 2^21247157461 is an apocalyptic number.

It is an amenable number.

21247157461 is a deficient number, since it is larger than the sum of its proper divisors (111074603).

21247157461 is a wasteful number, since it uses less digits than its factorization.

21247157461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85211.

The product of its digits is 94080, while the sum is 40.

The spelling of 21247157461 in words is "twenty-one billion, two hundred forty-seven million, one hundred fifty-seven thousand, four hundred sixty-one".