21498061897 has 4 divisors (see below), whose sum is σ = 23151758980. Its totient is φ = 19844364816.

The previous prime is 21498061883. The next prime is 21498061901. The reversal of 21498061897 is 79816089412.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 5973898681 + 15524163216 = 77291^2 + 124596^2 .

It is a cyclic number.

It is not a de Polignac number, because 21498061897 - 2¹⁹ = 21497537609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21498061867) 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, 826848522 + ... + 826848547.

It is an arithmetic number, because the mean of its divisors is an integer number (5787939745).

Almost surely, 2^21498061897 is an apocalyptic number.

It is an amenable number.

21498061897 is a deficient number, since it is larger than the sum of its proper divisors (1653697083).

21498061897 is a wasteful number, since it uses less digits than its factorization.

21498061897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1653697082.

The product of its (nonzero) digits is 1741824, while the sum is 55.

The spelling of 21498061897 in words is "twenty-one billion, four hundred ninety-eight million, sixty-one thousand, eight hundred ninety-seven".