21661465732457 has 8 divisors (see below), whose sum is σ = 21674149202496. Its totient is φ = 21648785980752.

The previous prime is 21661465732433. The next prime is 21661465732483. The reversal of 21661465732457 is 75423756416612.

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 21661465732457 - 2¹⁶ = 21661465666921 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21661465732396 and 21661465732405.

It is not an unprimeable number, because it can be changed into a prime (21661465732057) 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, 10768028 + ... + 12620354.

It is an arithmetic number, because the mean of its divisors is an integer number (2709268650312).

Almost surely, 2^{21661465732457} is an apocalyptic number.

It is an amenable number.

21661465732457 is a deficient number, since it is larger than the sum of its proper divisors (12683470039).

21661465732457 is a wasteful number, since it uses less digits than its factorization.

21661465732457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1859167.

The product of its digits is 50803200, while the sum is 59.

The spelling of 21661465732457 in words is "twenty-one trillion, six hundred sixty-one billion, four hundred sixty-five million, seven hundred thirty-two thousand, four hundred fifty-seven".