21495078544 has 15 divisors (see below), whose sum is σ = 41647850953. Its totient is φ = 10747246048.

The previous prime is 21495078523. The next prime is 21495078547. The reversal of 21495078544 is 44587059412.

The square root of 21495078544 is 146612.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 8615552400 + 12879526144 = 92820^2 + 113488^2 .

It is a super-2 number, since 2×21495078544² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21495078547) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 568122 + ... + 604774.

Almost surely, 2^21495078544 is an apocalyptic number.

21495078544 is the 146612-nd square number.

It is an amenable number.

21495078544 is a deficient number, since it is larger than the sum of its proper divisors (20152772409).

21495078544 is an frugal number, since it uses more digits than its factorization.

21495078544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73314 (or 36655 counting only the distinct ones).

The product of its (nonzero) digits is 1612800, while the sum is 49.

Multiplying 21495078544 by its sum of digits (49), we get a square (1053258848656 = 1026284²).

The spelling of 21495078544 in words is "twenty-one billion, four hundred ninety-five million, seventy-eight thousand, five hundred forty-four".