21697051007 has 4 divisors (see below), whose sum is σ = 22839001080. Its totient is φ = 20555100936.

The previous prime is 21697050979. The next prime is 21697051009. The reversal of 21697051007 is 70015079612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21697051007 - 2¹² = 21697046911 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21697051009) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 570975008 + ... + 570975045.

It is an arithmetic number, because the mean of its divisors is an integer number (5709750270).

Almost surely, 2^21697051007 is an apocalyptic number.

21697051007 is a deficient number, since it is larger than the sum of its proper divisors (1141950073).

21697051007 is a wasteful number, since it uses less digits than its factorization.

21697051007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1141950072.

The product of its (nonzero) digits is 26460, while the sum is 38.

It can be divided in two parts, 2169705 and 1007, that added together give a palindrome (2170712).

The spelling of 21697051007 in words is "twenty-one billion, six hundred ninety-seven million, fifty-one thousand, seven".