21661251540034 has 16 divisors (see below), whose sum is σ = 32661227819808. Its totient is φ = 10774179032832.

The previous prime is 21661251539999. The next prime is 21661251540067. The reversal of 21661251540034 is 43004515216612.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12030529 + ... + 13713355.

It is an arithmetic number, because the mean of its divisors is an integer number (2041326738738).

Almost surely, 2^{21661251540034} is an apocalyptic number.

21661251540034 is a deficient number, since it is larger than the sum of its proper divisors (10999976279774).

21661251540034 is a wasteful number, since it uses less digits than its factorization.

21661251540034 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1716369.

The product of its (nonzero) digits is 172800, while the sum is 40.

Adding to 21661251540034 its reverse (43004515216612), we get a palindrome (64665766756646).

The spelling of 21661251540034 in words is "twenty-one trillion, six hundred sixty-one billion, two hundred fifty-one million, five hundred forty thousand, thirty-four".