21223655388537 has 32 divisors (see below), whose sum is σ = 32417218068480. Its totient is φ = 12099151776960.

The previous prime is 21223655388517. The next prime is 21223655388587. The reversal of 21223655388537 is 73588355632212.

It is not a de Polignac number, because 21223655388537 - 2⁸ = 21223655388281 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21223655388517) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 349600728 + ... + 349661430.

It is an arithmetic number, because the mean of its divisors is an integer number (1013038064640).

Almost surely, 2^{21223655388537} is an apocalyptic number.

It is an amenable number.

21223655388537 is a deficient number, since it is larger than the sum of its proper divisors (11193562679943).

21223655388537 is a wasteful number, since it uses less digits than its factorization.

21223655388537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99773.

The product of its digits is 72576000, while the sum is 60.

The spelling of 21223655388537 in words is "twenty-one trillion, two hundred twenty-three billion, six hundred fifty-five million, three hundred eighty-eight thousand, five hundred thirty-seven".