212000021557 has 4 divisors (see below), whose sum is σ = 212131946016. Its totient is φ = 211868097100.

The previous prime is 212000021539. The next prime is 212000021567. The reversal of 212000021557 is 755120000212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 212000021557 - 2²⁷ = 211865803829 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 (212000021567) 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, 65959819 + ... + 65963032.

It is an arithmetic number, because the mean of its divisors is an integer number (53032986504).

Almost surely, 2^212000021557 is an apocalyptic number.

It is an amenable number.

212000021557 is a deficient number, since it is larger than the sum of its proper divisors (131924459).

212000021557 is a wasteful number, since it uses less digits than its factorization.

212000021557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131924458.

The product of its (nonzero) digits is 1400, while the sum is 25.

Adding to 212000021557 its reverse (755120000212), we get a palindrome (967120021769).

The spelling of 212000021557 in words is "two hundred twelve billion, twenty-one thousand, five hundred fifty-seven".