69069621721 has 9 divisors (see below), whose sum is σ = 70996816191. Its totient is φ = 67193413992.

The previous prime is 69069621701. The next prime is 69069621757. The reversal of 69069621721 is 12712696096.

It is a happy number.

The square root of 69069621721 is 262811.

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., 61804446025 + 7265175696 = 248605^2 + 85236^2 .

It is not a de Polignac number, because 69069621721 - 2²¹ = 69067524569 is a prime.

It is a super-2 number, since 2×69069621721² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (69069621701) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 9720456 + ... + 9727558.

Almost surely, 2^69069621721 is an apocalyptic number.

69069621721 is the 262811-st square number.

69069621721 is the 131406-th centered octagonal number.

It is an amenable number.

69069621721 is a deficient number, since it is larger than the sum of its proper divisors (1927194470).

69069621721 is an frugal number, since it uses more digits than its factorization.

69069621721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14280 (or 7140 counting only the distinct ones).

The product of its (nonzero) digits is 489888, while the sum is 49.

Multiplying 69069621721 by its sum of digits (49), we get a square (3384411464329 = 1839677²).

The spelling of 69069621721 in words is "sixty-nine billion, sixty-nine million, six hundred twenty-one thousand, seven hundred twenty-one".